In my tourist days, I stayed at the casa marina. Nice intermediate resort. It is right in Sosua so it is easy to get out and about.
Make sure to check out Sosua Bay and Cabarete beaches. You can easily get a taxi to Cabarete and sosua bay is a 7 minute walk from your hotel.
A trip into Puerto Plata will be interesting for all of you. Yes take ride up the cable car if it is a nice clear day, check out the Malecon, buy your rum to take home at the grocery stores here in Puerto Plata.
Most likely your children would enjoy a jeep safari, there are many offered. Find the one that appeals to you.
A day on a catamaran is always nice if you like the water!
Make sure to also get out of the resort and into the real Dominican!!!! Find a taxi driver who speaks english, negotiate a daily rate and go explore!!!
Go to Rockys restaurant in Sosua, it is around the corner from your hotel. You will find many helpful people there and the food is good....
Bring school supplies for the kids! One of us can help you get them into the hands of the right people.
For weather, check out both the Puerto Plata weather thread and the Cabarete thread! You can expect, sun, rain, hot humid conditions that time of year! Bring good mosquito repellant, you will need it.
Most of all, just plan to enjoy your holiday. Do lots of reading here on DR1 and you will come prepared......