St. Louis CFII:
Most traditional Guardsman fly about 6 or 7 sorties a month. Since I'm still on active duty, I haven't messed with the FTPs, GTPs, UTAs, and RUTAs (all the different 'drill' pay periods). Basically, you have to fill in the training squares to maintain your combat mission ready status. So, the Reader's Digest version of the answer to your question is anywhere from 7 hours to ? hours of flight time. Just because an individual is a traditional Guardsman doesn't mean he or she won't pick up extra available days to do some more flying. There are too many variables to say that there is an 'average', especially with the way the airline industry is right now (lots of furloughed guys who are 'traditional' Guardsmen taking temp technician tours, etc.)
Just because the 'Hog is slower than a Viper or Eagle doesn't mean that the Hog driver will get any more or less flight time. Sorties are scheduled around range periods, air refueling track times, etc.
As far as 'seasonal' training, do you mean the annual tour (AT)? Some guys break it up and do two one-week training periods, some guys use it all at one clip for a deployment, and still others break it up for airshows or aircraft drop-off/pick-up runs.
If you mean 'seasoning', or the active-duty period after you come back from the school house, then it is 254 days of active duty. You can extend that by coming off the seasoning orders and using up 'traditional' Guardsman pay periods (the FTPs, UTAs, etc.) but you will not have medical benefits, housing allowance, and some other things that you normally have on active duty orders. For a single guy that might be okay, for a guy with a family it's very not-okay. The trick is to get your finance guys to keep paying you with the changes from coming off active-duty orders, then going back on them after you burn some FTPs or UTAs...and from talking with friends in other units, most finance departments' track records aren't the best under these circumstances.
Our unit has no 'max distance requirement', but I will tell you that it helps to be local, especially when you're trying to get hired off the street with no experience in the A-10. Our pilot selection board isn't until September (I think the deadline for application packages is sometime in August), but we already have a healthy stack of well-qualified individuals who happen to be local or already in the unit. I wouldn't ever tell you not to apply, but those individuals who are very serious about it sent in their packages a few months ago and have visited the squadron on a drill weekend to get some face-to-face time with the pilots. Bringing a case of the squadron's preferred beverage is highly recommended as well, so when in doubt, call the operations number to find out what they drink.
Hope this helps, and good luck in the future!