Berkeley Springs is built around its warm mineral springs, so start in the state park and museum before branching out. The best day mixes a soak or footbath, a walk through the small downtown, an art stop at the Ice House, and a drive up to Prospect Overlook.
Cacapon Resort State Park, south of town, is the outdoor counterweight: wooded trails, lake recreation, and ridge scenery. It is close enough to count as part of a Berkeley Springs day rather than a separate trip.