Five nights in Dominican Republic. Should we do the Dominicus or Las Terrenas/Samana peninsula area or both?

We are a couple in our mid 30's headed to Dominican Republic for six days five nights. Hoping to avoid Punta Cana or major tourist traps altogether.

We are looking to be near beaches, do some snorkeling, be near nature, and be able to walk around to restaurants. No mega resorts. Just a balance of peace and quiet, nature, turquoise beaches, and a walkable boardwalk/restaurant area would be nice.

We are wondering, should we stick to either Dominicus or Las Terrenas areas, or should we do them both? If only one, which one? We do like to explore/stay active but also to relax and not stretch ourselves too thin.