My Wife and I are both 60 or almost, and I can relate a little to where you are coming from. First off, the RIU has a terrible reputation, so you may want to mark it off your list. You may want to add the Westin Playa Conchal. If you plan to have your own transportation, this is not a bad location, and it certainly has both a good reputation and very good reviews here on this site. If you did decide that you want to look around town and shop or go to one of the local cafes, or for that matter take a cruise, Tamarindo is just a short drive away. I will suggest that you don't try to do Arenal and hot springs as a day trip. It would be better to split up you stay by staying part time in the Arenal area and part time at the beach. Just my take. My wife and I will be going back down in October, and we will be moving all over the country in our two week stay.