Sort of depends on how far you want to go.
If you get out of POP area and head South, you have the option of going to Monte Cristi, and exploring the little towns of Guayub?n and Casta?uelas, along with the towns on the road.. Interesting places to distribute school stuff...They rarely see anyone non-Dominican.
If you go to the East (after going South to the Duarte Highway) you will see SAntiago, the largest city in the northern half of the country. You would enjoy the Eduardo Leon Center, a new museum of things Dominican.. then you can go to Tamboril, Canca la Reina, Canca al Medio, San Victor, and Moca, by the back way. You can return by going across to Jamao and eating at the Cafeto, a georgeous hillside restaurant with breathtaking views...
OR, you can go West straight from POP, and visiti Maimon and Luperon and El Castillo, cross the Bajabonico to La Isabela and go on to Estero Hondo and Punta Ruc?a.
Or, you can go East from POP to Cabarete, Gaspar Hernandez, R?o San Juan (Laguna Gr?-Gr? and the Cueva de las Golondrinas)
Playa Grande Abreu, Cabrera, Nagua, Sanchez and Samana, where you can watch the whales cavort...
Need more??
HB