More than you asked, but.....
You need to be in line at the airport 2 hours before flight time. If you're taking a taxi, plan to leave the resort 30 minutes before that. (It'll only be a 15-20 minute ride.) If you are taking a shared Thomas More van, they'll pick you up about 3 hours ahead of your flight time. If you have arranged for private van through one of the other services, ask for pick up 2.5 hours before flight time.
If you paid your bill Friday night, you can put Saturday's breakfast on your credit card or pay cash, thus avoiding check-out line Saturday.
Flying out first thing in the morning - e.g. a 7AM flight - means getting up and out very early, but there will be no lines. We prefer to fly later, maybe around 3-4, so we aren't rushing around, but then there will be airport lines.
Don't worry about the airport transportation issue till a few weeks before you fly. Transportation can be arranged at any hour, and you will get to the airport. Just pick the flights that seem best to you depending on when you get home, number of stops, price, whether you are morning people, etc.