Dominican Republic Plan

I plan on flying into Puerto Plata and out of Santo Domingo on my way to South America in June and have a couple questions:

- Can anyone recommend beaches near Puerto Plata that isn’t overrun with cruisers and resorts? A good beach to hike/run would be ideal.

- After that, I plan on heading to the highlands/Constanza/Valle Nuevo. Will I be able to take local buses without too many transfers? From there, I’ll head to Santo Domingo.

- Does this all sound like a good 10-day plan? I’m doing it this way because the beaches in the north look much better.