The town of Rio San Juan is nice, but quiet. Not much to do in the town except for the Gri Gri Lagoon tour, but do not expect an extravagant tour. Also, just east of Rio San Juan is Playa Caleton. An excellent beach to hang out at, not very big, but very nice. The locals have plastic patio tables and chairs they let you use as long as you purchase from them (Presidente, drinks, you can even order dinner while hanging out there and they bring it to you). If you enjoy the simple life, I highly recommend both of these. Every trip we always stop and stay a few nights in Rio San Juan. Its not a party town but they do have a few places you hang out and chill at night over a few Presidente's (or alot). Let me know if you have any other questions.
Kelsey