Dealing with the guest list we made 3 seperate lists to get us started.
The first list was the "Must Have" list, the second list was "Love to Invite" list, and the 3rd list was the "Would Be Nice to invite list." We also are paying for the wedding, so in our case we did not invite anyone on the 3rd list. We ended up inviting all of the people in the 1st list and a few in the 2nd list. We ended up inviting about 75-100 people and we had 40 book to come. It ended up perfect! We wanted a small wedding with just close friends and family, and that is what we have. Since we are paying for the wedding I didn't have to have too many conversations about my mother and father's guest list. We invited a few of the people on their guest list, but most of them are not coming. Maybe you could as your parents to divide their guest list into those 3 categories to get you started.
Also, FYI....I was surprised at how expensive everything at the resort is. Even the basic things are priced really high. I felt like I needed to have certain things due to the fact that people were traveling so far and speding so much money to come. That made our decision to have a smaller wedding much easier. Hope this helps. I know what a sticky subject that is.