Probably your best bet is to join a club that is in the area where you plan to do the majority of your riding. Many of them have activites all season long it's just a matter of getting involved with the club instead of just sending off your membership dues to get a discount on your registration cost. There are a couple of sizable clubs in the lakes region and I don't think any one of them would be a mistake to join. You can check them out on the NH Snowmobile Association web site -
http://www.nhsa.com