Remodel insulation

Well, insulation ain’t cheap. And remodeling an old and rotted travel trailer provides likely 0 or negative ROI. 
Id be looking at Habitat for Humanity or Jobsite scraps of anything from open and closed cell foam to fiberglass batt. 
Idk how but if you could get ahold of a truck load of shredded paper from them outfits that dispose of documents, that would work too just be more of a challenge to get the walls stuffed. I’ve thrown away enough old blankets and towels that some judicious use of a stapler could make that work too. 
Point being, pricing just 1” foam for my 28’ enclosed trailer was $400-600 for eps or xps and then another $500 for some cheap white mdf sheeting. 
If you have 2” walls double the insulation cost. 
Min $1000-1500 for insulation and sheathing.  Is it worth it? Are you going to see enough Heat or AC required days to see more value in spray foam or xps? 

Great points on the remodel! One thing that often gets overlooked during any renovation is debris and junk removal. Whether it's old insulation, drywall scraps, or leftover materials — having a plan for cleanup makes the whole project much smoother. Learned that the hard way on a few home projects!

closed cell is absolutly worth it if you can find some one who will spray a rv.  second best would be a good high r value ridgid foam board that you cut a little smaller then use expanding door and window spray foam to seal it around all edges. 

the thing with spray foam is if they spray it properly it is going to bond to the surface and lock everything togeather increasing the strenght of your wall or celing system, but at the same time it will make it harder for repairs.  the second benifit of it is you know it makes an absolute seal keeping any migration of heat due to air flow out.  you can achieve that with foam board but it takes diligent sealing with the expanding foam.  

last thing is ya it might be a bit more expensive but it is easier fo you in the long run.  it conforms to shapes, goes over wires, and plumbing.  foam board thoes areas will take the most time.  if you have it in a drivable state, when you ask spray foam companies for a price tell them your willing to drive it to a location where they are already spraying if there is one close.  that will save you a ton of fees as there is a minimum setup and tear down just for them to start a job.  if they could sneak it in at the end or begining or lunch hour where they are already shooting, it might sace you a whole bunch of money.