Take a chicken bus from Rivas to Las Salinas and get out at the last stop. It is a 5km~ walk from where the bus stops to Popoyo Beach, but you should be able to hitch a lift or pay a local a small fee to take you the rest of the way.
The beach is long, but you should be able to walk almost everywhere in Popoyo.
The amazing Pacific sunsets.
Magnific Rock Hotel has panoramic views of the beaches and the rock below.
There are hot springs in nearby Las Salinas (US$3 entry fee), perfect for relaxing after a morning's surf.
Surf (board rental US$10/day), or walk along the beautiful white sand beach.
There is a small tienda in town for your basic needs, but it is maybe better to stock up in Rivas prior to travelling out here. You may be able to pay for your accommodation by card, but there is no ATM (the nearest being all the way in Rivas), so bring enough cash.
Every hotel has its own attached restaurant (expensive) and there are few cheaper comedors. You can also buy a fish off some of the local fishermen and have a barbeque on the beach.
There is an old local man on a bicycle who sells delicious freshly squeezed fruit juices in plastic bags for C$10.
Petty crime is quite common in Popoyo, unfortunately. Always leave valuables in an extremely secure location, make sure you lock your doors and windows, close the curtains and leave a light on if not in the room after dark - there have been a number of break-ins. Likewise, it is not a good idea to leave laundry outside after dark, as it may not be there when you wake up in the morning. The local police are next to useless, eventually you may track them down to fill out an insurance form, but don't expect them to do any actual investigative work, although everyone in town knows the few bad eggs who cause the trouble. It is mostly drunk and/or drugged up local men who are responsible, and they occasionally harass female visitors, so avoid walking the road or beach alone after dark.
Hitch back to Las Salinas and take the chicken bus back to Rivas, or jump out at “Gigante Salida” for Playa Gigante.