Some must haves:
*
Gas engine, such as GM 8.1L, 6.0L or 366 or 6.8L V10 by Ford.
*
Truck front, not E-series. Meaning GM G4500/5500 or Ford F450/F550.
* 2006 and newer
*
Fully converted for full-timing, more or less plug-and-play
* Mid-Atlantic on the East coast, ideally, though will travel around the east coast for the right model. I am in Washington DC area.
* Flexible on size, between 17-30 passengers.
Ideally a shuttle bus such as FasTrans as it fulfills all of these requirements.
This pics lists an ideal candidate, 28-person FasTrans shuttle bus: (sold and not mine).
https://gwinnettshuttle.com/listings/2009-chevy-c550