I know there are lots of posts about appropriate truck/trailer combos, and have read through many, but haven't found on that really matches our situation.

We currently pull a 3h all steel BP trailer.  Not sure on the weight, guessing 3500-4000#.  Pulled it for 6yrs with a regular chevy silverado 1/2 ton ext cab.  No problems at all.  Mostly just hauled 2 horses, but did haul 3 quite a few times, total horse weight about 4000 (1800, 1200, 1000).  Never any problems stopping, never any problems getting going.  Noticed towards the end that the engine was pulling pretty hard going up long hills.  Also had found that sidewind conditions pushing the trailer made the truck a little light.  So, when trading trucks, decided to move a bit bigger.  Got a 2008 chevy 2500HD 4WD with a 6.0l v8 gas engine.  Already set up with factory electronic brake control, hitch system, etc.  Didn't have a GN at the time, but was thinking about one down the road, so had a GN hitch installed in the bed at time of purchase.

OK, flash forward a couple years and we've pretty much outgrown the 3h bumper pull.  Actually, even though we have hauled 3h with it, it is a TIGHT fit, and we generally pull the front panel and run it like a 2h.  We are looking at a few different 4h GN trailers.  Not going to do a LQ for sure, but are likely going to extend the length a bit in DR & in horse area, probably adding about 3' total, making us in the neighborhood of 32-33' nose to tail I think. Am told the trailers wer'e looking at (aluminum or "mostly" aluminum) are going to be in the neighborhood of 5000#, but we are also kind of considering an EquiSpirit 3h safeload, that we could convert to 2 "box" stalls (the 2 box stalls is the real reason to go 4h, as we'll only occaisionally really need to haul 4, and would never "have to"), but by time we make it long enough to suit our needs up front, it would probably come in at around 7000# or a little more. 

Assuming a 5000# trailer, fully loaded with about 4500# of horses, another few hundred pounds of tack and supplies, we'd be running about 10,000#, maybe to be safe, call it 11,000# headed to a show.  With the Equispirit, add a couple K#.

Sooo, is my 2500HD going to handle this safely?  When I was buying the truck, I asked a couple local trailer guys and they said any 3/4 ton pickup could easily haul a 4h GN aluminum trailer.  Now after reading on this site, there is a LOT more involved.  Not sure I really want to get into all those details and worry about absolute max I can haul with my truck or bare miniumum to haul the trailers we're looking at.  Just want to safely handle whatever load I'm hauling without worry.  So, if the truck isn't enough, or even if its kinda borderline on this truck/trailer combo, probably need to rethink the trailer.  Going to a 1ton dually or even bigger is simply not in the cards right now.  We tow maybe 5-8k miles per year, and NOT driving a dually to work, so would be a huge waste.

So, after all the verbosity, what do ya think?  Enough truck for the trailer we are looking at? 

Off topic a bit, if we go to a big long GN, it seems a bit overkill for those times we are hauling 1 horse to a clinic, or vet, or hauling 2 20mile to go trail riding or something.  Is it normal to have a spare runaround trailer?  If so, what might be a good option...I guess we could keep the 3h BP, but would really prefer something a bit smaller, esp for when my wife needs to haul 1 horse on her own.  Would a 2h straight load GN be easier for her to pull than a BP?  She'd prefer a Brenderup, thinks she can pull it with her car (although even if they claim that, I'd NEVER go for it), but think they would be a bit pricey for a 2nd trailer, thinking more 3-5k type.

Thanks in advance for any advice.

Your GM 2500HD 6.0 gas burner truck with 3.73 gears is rated to tow about 9900#. With 4.10 gears it's something like 11600#.... That's with a bumper pull or a gooseneck. Max. GCVWR is 16000#, that's the total weight of the truck, trailer, you, horses and all of your stuff..... Some specs below on the 2010's, same as the 2008's.... Big changes came with the 2011's.

http://www.carsdirect.com/research/specs?cat=all&make=GM&modelid=136&acode=01C10GMT201B0&year=null

Ditto on the run around trailer. Having a second smaller trailer that is easy to hook up and maneuver makes life much easier. It doesn't have to be fancy or even pretty, but functional and safe. For a second trailer, I would prefer the rear doors to be a two piece with camlocks and no center post, or a one piece stock type. No rear tack, but racks and hangers in the forward tack room. I like slant loads over straight, but that's a personal preference. I also prefer GN's over BP, but most aluminum would not be available in your stated price range. I have seen some steel 2h GN for under 5K$.

This trailer is being advertised by a forum member. It wouldn't take much work to install two box stalls. Your truck could easily handle this trailer:

http://www.horsetrailerworld.com/home/trailerdetail.asp?ID=282895

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Depends on your finances whether you can afford two trailers.  Your current BP is paid for, so you may just want to keep it around. If you have room to store it.

I don't have the space for two trailers in my yard,  I don't want to invest the money in a second trailer, So I do everything with my 4H GN.  I don't ride on my property. So every time I saddle up, means that I also hooked up and towed someplace. Sometimes its 1 and sometimes its 5 horses squeezed in my 4h trailer.  I don't feel the need for a run around trailer. I'm very comfortable pulling my GN.

OK, I've heard many different things. 

Most of the "reports" or "reviews" show a maximum towing capacity of 13,000#.  Well, in the book it shows a max trailer weight of either 9,800/12,300  (depending on rear axle ratio 3.73/4.10) and lists the 13,000 as the max trailer rating with a weight distributing hitch.  I've got the 3.73 rear axle.  Weight distributing hitch.  Don't think that means I could go to 13000# though.

BUT, have also been told many times that these are tow ratings based on BP type hookups, and don't apply to GN trailers.  That if a truck can pull a 10,000# BP, its probably closer to a 15,000#, and maybe even higher.  Others say the weight rating in the book is max trailer weight regardless of trailer type.  So what is it.  From the limited times I've pulled a GN, a 3h GN sure seems a lot "easier" on the truck than my BP.  But I've only pulled a fetherlite 3h GN stock type with 4' sw dressing room.  We're adding about 6'-7' in length compared to that trailer.

If I have a max trailer weight limit of 9800# then that is the limiting factor...because no way I'm getting over 16000# combined weight if I keep the trailer under 9800#....just don't haul enough added weitht in the truck.  Tounge weights, hitch limits, etc all well within the limits.  However, if I can increase the max trailer weight limit due to GN type, then probably the 16000# combined weight becomes my limiting factor.  Max tounge weight is 3000# for GN, so don't think that would be a factor unless the balance was off putting too high % on the truck.  Hitch is rated for over 16000# trailer, so that isn't a limitation.

Hard to find reliable data it seems.  I'm a numbers guy and want to know XXX is my max based on this limiting factor and then I can adjust to whatever safety buffer under that I want, 10% or so probably.  But everybody seems to report differently.  Safest is to go ge a 1 ton dually with a high rear gear ratio and a huge deisel engine, BUT while I'm generally a "bigger is better'' kind of guy, its a bit overkill to use something that could easily pull a 45' massive LQ trailer.  Don't need to have a 50% buffer for my peace of mind.

Not worried too much about legal.  I've had a CDL for years, and no problem to get a DOT # I think.  Hopefully that should be it.  Maybe need to get the wife a CLD, be good for her to take some training and pas a test;)  Of course I'm "HER DRIVER" so she probably doesn't even get to triple digits in miles hauled in a year.

So, we can deal with the legal.  I just want to make sure I don't buy more trailer than my truck can haul safely and comfortably, cause I'm not up for trading trucks right now.