A sunny driven GT just shouldn't eat up tires that much. Especially since you can rotate them.
I'm running a staggered setup, wider on the rear, so I can't rotate. TireRack told me to expect about 15,000 miles.
The stator and gaskets will be about $225, and labor would be $320. I wasn't far off on that. Didn't ask about the rocker box labor time. I also need to put on a new rear rotor. I already have the rotor.
This is part of the reason why renting a car seems easier. Everything that needs to be done on the bike can be done sometime this year, except the stator. For a trip, it all needs to be done now.