Where is the SXM antenna mounted in your car? What kind of radio do you have?
The radio I have is an add-on tuner designed for the Kenwood car radio I added to a 2001 Toyota Camry. The satrad antenna is magnetically mounted just above the front windshield. Calhoun, Pike (IL and MO), and Jersey counties in semi-rural regions near St. Louis can be heavily wooded. Dropouts for me are rare. Another nice feature is how SXM will start a song from the beginning when you press a preset.
Vermont looks awesome, based on the photos I've seen, but the Great River Road region and MO 94 wine country might give the area a run for the money!