We stay in Estes Park at the Comfort Inn on the east edge of town. All kinds of lodging there, so just check out the type you like. Plenty to do in the town when you get back in from a day in the park.
As for caches, lots of EarthCaches in the park, many at normal pullovers without rigorous hiking. You’ll most likely be stopping in those spots anyway. Did a few regular quick caches in Estes Park, but nothing spectacular.
Haven’t been since 2013, so things might be different now. Just pick out a few caches to do, but mainly enjoy being in the park itself.