I recently sent a pm to a good soulmate who is coming here for a period of time and she was going to wiki the info ... but I'm sure she won't mind if I repeat some of it here, judiciously edited.
Infrastructure
Be very sure that you have water when the power is out... Usually, it would be a tinaco on the roof, that pressure feeds the house or apartment and not a water pump that works on electricity.
If you can, be sure that you have an inverter to supply 24 hours power to the house/apartment, or a generator that actually runs well, preferably diesel. It gets real old real fast if there is no water in the house to flush a toilet or wash the dishes. Even in these 'normal' times, we still have 6 to 8 hour power outages per day. No-one really talks about it any longer, because we all have inverters to bridge the period of outage and then we don't notice how long the black-outs are.
This sounds like fun and the family can do it together and so on, but we all have other things to do. If your infrastructure works, things are really much easier. Please remember UPS's for computers, unless you trust the inverter to do the safeguarding for you.
Keep in mind that certain areas are just plain noisy! Trucks, motos, cars, people screetching, chickens and noise from all levels. So, if you decide on where to live, take a little time and just listen at different times of the day .. morning, night and daytime. A nice place may just be very very noisy.
It is important to check the area, as well as the house/apartment, for safety against burglaries and so on. Your family needs to know that especially in the beginning, you may be targets for a quick burglary or a purse or phone snatching or something, just because you are new.
For a DSL modem (Flash), don't accept an answer that you can get flash in an area, ask if someone else has it, and verify physically in another home/apartment near by.
It will probably not be so easy initially to get a furnished place to rent, unless you work inside of the 'gringo' community for that - Dominican rentals are not usually furnished. Please please be aware of who you deal with. Please double check on the board if you feel that you want or need a 2nd opinion. Actually, just double check on the board anyway... Your community is very important.
For leases or rental contracts, it is better to consult an attorney, even if it is just a quick consultation to ensure that you're doing the right thing - to ensure that the previous electricity and phone lines are paid up. If the previous stuff is not paid, there is no way that you can get services, unless you pay it all up. Don't expect a bill to arrive at your door. It may, or may not. At the right date in the month, go and pay your electricity and phone, even if you do not have a bill. Keep these two services in your hands .. don't let the landlord do it if you have a house.
Anyways, I hope these notes help.