road-trip transport

i intend along with one friend to do a full circuit of the u.s. this summer, perhaps starting from either boston or somewhere in florida. (we are from the uk). obviously we will need to procure some sort of vehicle, and we were wondering if buying something like an old schoolbus might be a cheaper option than hiring say, a winnebago.. does anyone have any tips/suggestions on the bus idea or just on the trip in general? does anyone perhaps even have a bus they might want to sell in these areas?
we are giving ourselves about three months for this ambitious project.

Purchasing an old school bus sounds like much more work and expense than makes sense. Not for the faint of heart.

we are from germany...but we are workin in the states right now. we are planning a roadtrip through the states this summer. the only problem we have is the vehicle. buying an old school bus was one option but the question is is it gonna make the 7500miles trip? I work about 1h north-west of boston.

Most buses were designed to go one million miles. But finding one in good condition is going to be tricky.