If you can't drive it home, the cost to get it home will start at ~$4 per loaded mile & go up from there.
So, you're going to have to do some work on the brakes before you can drive it home.
If it were me, I'd go look it over real closely - Look down the body - if it sags or bows, that's gonna mean lots of work. Look for rust in the air beams. How is the curved glass? If the radiator is shot, you're looking at $1000 minimum to replace the core. Are the tires up to a road trip?
Look for body skin corrosion on the lower level behind the driver. Look for popped rivets.
If you like the look of the bus & the original stuff that is important to you is still there, buy the brake treadle valve & install it & do what ever else is required to ensure road worthiness - then take it for a test drive. If you like it, make a deal & pay the man. Then drive her home.
BTW, I have paid more for less - - - lots more for lots less.
Bottom line is the market is quite limited & you can easily spend several thousand dollars flying across the country looking at possible candidates.
The initial purchase price is the smallest part of the cost of converting one of these.
Good luck with your quest.