The travel arrangements were such a pain in the ass. We ended up going through a travel agent, she was having a hard time getting rooms blocked but finally we did. Our guests had a month to put down a $100 deposit to save their room. For the rooms our TA's rate was cheaper than the resorts group rate. And as soon as airfare came out, our guests had like a week to pay in full their airfare. We got a group rate for the airfare.
The one thing great about having a TA is that she/he can answer all of your guest's questions reguarding travel and they can also make sure people make their payments on time. Of course I still had to stay on top of my family, all procrastinators.