Fat tire bike? I just bought this one. I'm in the process of decking it out with a rear rack, scabbard and an anchor point to pull a game trailer. Also have the mud tires to put on it.
Yamaha TW200. In most of the country you can find a nice, clean low mileage one for under $3K or an older one for $1500. They are supposed to be pretty much bullet proof, We'll see. Plus they are street legal.