As long as they sell the bus to you for under $1500, it's rust free, and your willing to do the work, go for it.
Any more than that and I would look for a better one.
On the plus side you would be good for another million miles after the in frame rebuild.
Engine work can be fixed. Bad rust is a deal killer.
"Don't argue with stupid people. They will just drag you down to their level, and beat you up with experience."
Patently waiting for the apocalypses to level the playing field in this physiological game of life commonly known as Civilization