I agree with Speedo66 about the W being a decent buy. What does a new Bonneville or W800 cost today? Also it appears to me that W650 prices are going up.
I would not be worried about the lack of use. My 2001 W650 that I bought last year had 2k miles on it and has not had any problems. These are first class quality bikes.
Vince @ SWFL or WNC
2001 Kawasaki W650
2012 Dong Fang DF250RTB hard tail bobber
2014 Sky Team ST125-8A monkey bike
2014 Ice Bear PBZ110-1P monkey sidecar