Spray foam for travel trailer ceiling and walls?

My opinion, if you're going to do all that prep work yourself, do the spray yourself. The biggest part of the job is the prep. That's what really goes into the cost. But I doubt a pro would just come in and spray very cheaply. He's still gonna want to make his money.

You can rent the spray guns and air compressor at a hardware rental shop. Probably sell the medium as well, but if not, any big box hardware store will have it.