Great ideas guys!  In addition to what you all have listed  1. definately diy save the dates and invitations. 2. limit guests attending and length of stay:(  I'm sure there are many more. I'm just in the early stages of planning!
We are definately using a travel agent. But I don't see the need to have a weeding coordinator outside of the resort. We are just using the one the resort provides. And so far it has worked out perfectly. It does take a while to hear back, but doesn't bother me. We just want a simple plan free wedding..
Welcome to the forum. My cost goal was about the same or less than yours.. I eventually decided that guests would just have to make their stay shorter..I don't know if that is an option for you though. Mexico would def make it easier to stay in that price range. Good luck.