For what it's worth - I had a roof leak early last winter and in a panic bought a new cover. Upon receiving it I decided it was too dangerous to haul that heavy cover up on the roof - roll it out, then climb up and fold it back up in the spring. Just not worth the risk and covers are known to cause wear during windy times.
My 11 year old 'rubber roof' is still in decent shape (leaks were from tree branch cuts) and I live 12 miles west of you. Search this site for rv covers and see what others have found. Most do not recommend covers.
A a car (RV) port or similar roof would be ideal.
Tom and Amy from Northern Virginia.
2000 Allegro 454/Workhorse P32/TST/Crossfire
Life is a DIY project - enjoy it.