Welcome to the Walters family school bus to Recreational Vehicle conversion project site
Believe it or not, there are lots of people who have already done the same thing. School Bus to RV conversions are collectively called "Skoolies" around the Internet. I liked the name, but wanted to personalize the idea a bit, so I decided to call ours a Skewly, to personalize it a bit. We "borrowed" ideas from lots of people who have already done this and came up with a few ideas of our own.
The main reason I wanted to do this little project was to have a hotel room on wheels that would allow us to travel across the US, Canada and Mexico in style for substantially less money than a new RV and even less than a very used RV.
We spent less than half the cost of a used Class C (class C RVs are those smaller RVs that are built on a van chassis) and have a unique RV that is made exactly to our specifications with all new stuff. The bus and engine aren't new, but the insides are all new. Plus, this thing has much more power than a similarly-sized Class C RV (the bus is 31 feet long) and can handle much rougher terrain.
If you are interested in doing your own School Bus conversion, go for it. There are a few school bus conversion forums on the Internet with lots of other crazies who are doing the same basic thing to varying degrees of detail.