Dan,
The vans are already in good shape, clean-wise. They are run thru an automatic carwash once a week. The vans don't really see dirt roads or such, and are mostly just light road grime etc.
The service manager I've been chatting with is a bowling buddy. I've known him several years, I don't think he'd bs me on purpose, and he said he really wants me to have the work. He says that they now pay $4 for the carwash, plus about 15 minutes of the drivers time, which is about $5. So your looking at $9 per truck per week. Best estimate is three locations within a 25 mile radius, and a total of 220-240 vans.
In order for me to take on this many vehicles, I will need another hot water rig. One is not enough. In order to cover my butt, I want a contract in writing for a specified period of time, to make sure that I can pay for the equipment outlay.
The thing is, I'm not a truck washer, and I don't really want to go that direction. But economics must rule. I just need winter work to keep bucks rolling in, and to give my guys winter work. Otherwise, I lose my full time help every year, and have to look for new guys every spring.
If I have two hot water rigs available, how many guys and hours might it take to wash 80 vans? I don't want to two-step, I'd prefer a good soap with a little brushy brush when needed.