A GN doesn't follow the truck as accurately as BP trailer. The GN will cut across the corners with less of a radius than the truck. You probably won't know how much until you hook up and try it. The distance from the ball to the centerline of the axles can vary with each rig, so the turning radius will vary with the actual distance.

When you pull a GN you will have to swing wide for tight corners, to avoid pulling the tires off the road's edge, more so than a BP.

If your landscaping allows for the turning radius of the truck, the GN will fit within that circle. The inside driveway's width, will have to be made wider to accommodate the trailer's wheel tracks.

Others here know a lot more than I, so they can correct me if this is wrong.  I rented a 31 or 32 foot goose neck flat bed to pick up two little classic cars.  That trailer may have had three axels - I'm not sure if it had two or three.  I could turn that very sharply but was advised to be careful to not turn it very sharply.  The man said that I would pop the tires off the rims.  I do know that I got in a very tight spot with it and turned that trailer pretty much "on the haunches":) but was very careful to not do that long. 

I haven't faced that with my little 18' horse trailer.

That is good to know. I always wondered.  That was a very big trailer and the little opel gt's didn't overload it I'm sure. I'm not surprised that guy was wrong, but it did make me more cautious.

There's really no specific formula because there are far too many variants. How tight a turn that you can make is based on the length of your truck bed; placement of the GN hitch; flat-front trailer or tapered; axle placement on the trailer, etc.

When you are shopping for a trailer, you could ask to wet the tires and drive it as tightly as allowed then measure the tracks. This is based on you having a GN hitch installed in your tow vehicle before shopping.

Remember that when you are making SUPER tight turns that do not compromise your truck's rear window, you WILL be dragging trailer tires cross-ways at some point.

If you are planning on a semi-circle drive in your front yard, the best thing to do, is to wait until you have your trailer, then drive it across the yard. A wide "lane" should give you the space you need without having to have a ginormous diameter to your circle as the trailer will cut inside while the truck goes wide.

ANOTHER option. Ask your friends who have GNs to help you. Again, wet tires on dry pavement. then chalk it in and take measurements. Good Luck!

Our rule of thumb when turning--take every thing you have..in other words, turn as wide as the locale will let you to prevent tire and AXLE problems. I think a lot of axle/bearing issues are from turning to short dragging tires sideways not collisions with pot holes/curbs/etc.

Surprised no one has mentioned--when you turn around, try to do it unloaded. We have a fairly narrow drive in front to the barn--we get home and unload than turn around to put the unit in the shed. We load after we are pointed out when leaving. To me, that has to prevent some tire/axle issues.

Our 18' gooseneck stock trailer behind a 4500 Chevy needs about 60' or so to make me feel comfortable. It will do it in 32' but not unless I absolutely have to. The 4500 turns shorter than our 2 door car. With this trailer, you can turn a 360 and not even move the front trailer tires easily--scary.

Good luck!

lol, I love this description!  I was/am pretty good with a bumper pull and when I went to the gn, I thought it was odd in the way it backed - this is a great description.  I still like the little "cutting horse" feel, but the other advantages of the gn outweigh that I suppose:)