LePaul, ask the ISP's you are going to contact who they use for thier backbone connections as well.
Avoid the ones thet use Sprint for thier backbones. Also ask the ISP if they maintain thier own equipment or if they are leasing the dial-ups from someone else. The ones that use someone else will not have the quality of support you might want. Thet also do not have direct control over thier dial-up equipment, which is a problem in my opinion.
In your part of the country (Maine?), BBNPlanet/Genuity and PSINet have the best backbones. So if you find an ISP using either of them, then you should be golden to AH and the Internet.
If you are going to use a 3Com modem, ask the ISP if they are using 3Com Total Control terminals servers. If they are, you probably will get a more stable connect.
Hope that helps.