I personally do not have much experience with a building trailers, i do however have minimal knowledge about remodeling older trailers and things i have found out
only through experience (thats what im asking from you) and to share your experiences and lessons learned in one post so newbies like me,and others can look in one spot.
I will start even though my experience is on a current remodeling job im doing on an old school 72 Kayot
Lessons Learned:
Lesson#1 I bought a trailer that looked very clean and in good shape...The guy told me he put a new roof on it, however when i got it back to my house 2 days later i noticed above the bunk bed Black mold.His idea of a new roof was patching the hole where the rain was coming in for years! So i ended up replacing the entire ceiling front to back

Lesson#2 Electrical stuff! For goodness sakes i think i have rewired and redone almost everything that was suppost to be working! check running lights, turn signals, and brake lights before! (sometimes its more than just a burned out bulb (i currently have about 7 out of 12 running lights and side markers with ground problems
Lesson #3 Painting old dirty laminate!!!!!! I hope you never have to experience this but if you do like me use TSP detergent to clean the walls or get a sander with some harsh 40 grit sanding and sand that crap before you even try....otherwise you will literally have to wait 3 days for it to actually stick without scratching right off!
Mistake #1 Buying this trailer

Mistake #2 Dont hook a hood range wrong! You know the one with a light and a fan.....you will fry those knobs that you cant buy anymore (at least for my trailer).
Mistake #3 Dont try to resolder old copper pipe! just buy a new piece with compression fittings....He forgot to winterize it

Must knows....If you decide to remodel a 40 year old camper keep plenty of Coors light on hand and qit your day job because you now have a whole new set of problems!
Mainly i was hoping someone could give me some information on new builds...but this is all the information i have to offer as of now