Your advice please...

As for the time of the year, you should try to avoid the hurricane season. The "official" season is from June 1 to November 30. August and September are the months  that PR had most of its storms.

If you like the beach and want to take your kids to the beach, I would avoid the North coast locations that you mentioned (Dorado and Aguadilla) The beaches there are great for surfing but not too good for small kids. Cabo Rojo would be a good choice. I personally love Boqueron. Mayaguez is close for all your shopping needs.
You may want to check out Rincon (north of Mayaguez) as well.
If you don't need to be on the main island, have a look at Culebra and/or Vieques (two small islands off the East coast). Some of the best beaches of the Caribbean are on these two islands.

As for broadband, it's available in most places. If you husband has a mobile broadband contract with one of the US cell phone providers (AT&T, Sprint, Verizon) he can use it here at no extra charge. Most Hotels/resorts offer broadband connections; I don't know about rental apartments - you'd have to check with the owner.

Thank you!  I was also leaning toward the west coast, but I thought perhaps it would be nice to be close to San Juan (without being in it).  I would much rather have calm beaches though.  Can we day trip to Old San Juan from Boqueron or Mayaguez or would we need to stay a night or 2 to see some of the sights over there?  Are these towns walkable?

Do you think that there would be enough culturally interesting things to do on Culebra or Vieques?  Or is it a quick and easy ferry ride to the main land?

Thanks for your info so far.

Jen