Massanutten in VA
Several of the larger resorts in Williamsburg VA offer extensive resort amenities to fill in between a month's worth of local sightseeing - Marriott (II), Wyndham Governors Green or Kingsgate (RCI), others - see TUG Resort Reviews
Same could be said for a few of the resorts in Gatlingburg/Pigeon Forge/Sevierville TN - Westgate (fine for exchanging, II), Wyndham (RCI), others - see TUG Resort Reviews
Larger beachfront resorts often have excellent activity programs and may be possible trades at the very beginning/end of summer or during the shoulder season. For example, in South Carolina, look into Marriott Grande Ocean on Hilton Head, Disney in Hilton Head (not on beach but good activities), the Marriott in Myrtle Beach, some of the Wyndhams in Myrtle Beach. In Florida, look into the beachfront Marriotts (II), Wyndhams (RCI), Disney (Vero Beach, II)), HGVC (RCI), others. Usually, the largest of these will offer plenty of resort amenities, scheduled craft activities, guided tours or walks, etc.
Westward, there are a large number of resorts like these as well, just more spread out on the map. We mostly went sightseeing from the Wyndham in Flagstaff AZ but there was truly plenty to do at the resort too. I've read similar about Wyndham in Pagosa Springs. Others may be better versed with western states travel.