Re radio there is a switch on the lower dash near drivers door that changes radio operation from either engine battery or coach battery try starting engine and placing switch to engine battery to see if radio works. Maybe the coach battery is dead? My 2006 Winnebago Chalet is the same as your 2005 Itasca Spirit or Winnebago Minnie.
The price seems good to me if their are no major problems.
Regarding the generator, if it has not run in a long time the carb is gummed up or like a previous post low on gas, I run my gen every 30 days for about an hour with a load. Let us know what you end up doing. Welcome to the RV owners world. Dick