MCO is very easy to navigate. You will come in at either terminal A or B and will pick up your luggage at that terminal. Each side has access to ground transportation. If you are renting a car, it is easy to drive around the airport...just follow the signs for the south exit and take the greenway to WDW.
As for security...when doing your return trip, keep in mind the two hour rule...you will need to be there at least two hours prior to your departure time to make sure you get checked in and through the security checks. I have seen people bumped with 45 minutes til there flight because they wouldn't get through the security check in time! The plus side of MCO is that if you get there two hours early and get checked in right away, you can walk around the airport shops for a little bit before heading through security and two your gate...saves sitting in the gate area for an hour and half.