I am trying to decide what to use for the walls in my living quarters. I am worried about weight. I don't really want to use just cheap paneling but som eof the other options gets pretty heavy, I lookes at some leather looking walls but it required backer board which is going to make it heavier to.

Also what type of insulation do I use. I seen the big rolls and just plain styrofaom boards.

I hope this helps, I looked the weights up on the net a few years back, I was interested in the weight of the LQ's I build. A 1/2" sheet of AC plywood weighs approx 46lbs. A sheet of Luan weighs approx 11 lbs. for a difference of 35 lbs.

Now go to a trailer, 4ft. shortwall will have an 8ft. longwall and an 8ft slantwall. You will also need a sheet for the "jackwall" and 3/4 of a sheet on each side in the nose. Total will be 7.5 sheets of Plywood times the 35 lbs. extra per sheet = 262.5 lbs. heavier using 1/2" plywood. That is really a little high as most trailers are only 82" on the side walls and you don't cover the entry door. But lets stay with the 262lbs. The extra weight is a trade-off I'll take to be able to mount a cabinet anywhere I want to, or to be able to drive a screw anywhere I want to. If the trailer is an 8ft. shortwall, add two more sheets, 12ft. shortwall, 2 more, you get it.

If you use the plywood from Home Depot it is smooth enough to wallpaper just like a house, just spackle the seams and put a coat of wallpaper sizing on it. I have trailers out there that are 7 yrs. old that were done that way. Still look great.

I'm planning on using some wood planks (though panels or wallpapered plywood sure sounds easier). The biggest PIA I'm having is the ceiling (since I realized it tapers and doing the ceiling with the planks in the direction I wanted will be complicated - for me at least) and putting in all the furring strips and framing the windows and such.

Anyone wanna come help. LOL!

Well, HW, it seems you've created a lot of questions just by answering one.  Here's mine:

When you do a Kiefer, you put your insulation between the studs, then mount 1/2" plywood directly to the studs without furring strips, and a cabinet can be mounted directly to the 1/2" plywood and will still have enough support, or do you make sure to hit a stud somewhere along the line?  Where does your wiring go in all this? And how do you keep it accessible in case of repairs at a later date?

Maybe I should quit answering questions, just joking, I'll share what little I know. As far as why I use firring strips there are two reasons, 1 is if the wall is not flat from the floor to the top rail. If you can take a 1x4 on edge and lay in along a wall stud and it is not flat or there isn't an easy fix to make it flat, then I will use firring strips. 2 is on 4 Stars the Aluminum Studs have a thicker wall than other brands, you cannot use a self tapping screw in the wall studs of a 4 Star trailer, they will need to be drilled first. So it is easier to use firring strips and attach the walls to them JMHO. On Kiefers I mount the 1/2" plywood directly to the studs(lighter weight aluminum) and then you can mount a cabinet to the 1/2" plywood, I haven't had one fall off yet. My wiring is just like the factory built trailers, behind the wall, you will not have access to it once the walls are up. If you notice on the Kiefer trailers the bottom 3 inches of the wall is out about 1/8", I use a router on the backside of the plywood to make it lay flat. There will also be a lip at the top rail, I do the same thing there.