I've used an independent for body work, and they did a great job, although it was a sheet metal style trailer. I would at least discuss the job with them for our flat wall trailer. They are not a selling dealer, so they make or break their bones on quality of their work. Also, for body or structural work, talk to your insurance agent for references, even if your insurance won't be paying a claim.
For appliance type stuff, a mobile repair guy would probably be my first call. I've never used one, but if my heater goes out, I don't see why I would haul the trailer somewhere and leave it for god only knows how long. At least with mobile, if you can get them there, it will be a speedy repair.
Fixing stuff myself is always my first option. It isn't rocket science, but you do have to know your own limitations.
