Thinking about converting and ambulance to an RV

OP,, I might suggest that you look to spend more of your budget in initial purchase and find one that is in better shape. In my area, used Class C's are rough and often in very poor shape. I think you would be better served to spend $25K on a good quality vehicle to start and $5K on upgrading. You are more likely to find a solid vehicle at $25 than at $10... at least in my experience.

Good luck though!