Parking at the parks is extremely easy, and basically you are guided everywhere by CM's along the way. The parking fee covers a full day, and allows moving from park to park without paying again during the day.
Driving from MCO to WDW is extremely easy. There are signs the whole way. You will probably even see a Magical Express bus at some point at the airport. Follow that bus if you like, but the signs should be sufficient. WDW is southwest of MCO.
Getting around within WDW is not that hard, but the signage leaves a bit to be desired. The signage is fine to get from park to park, but not so great if going to a resort. If going to a resort, it helps to know which park the resort is closest to, since you'll see signs saying "EPCOT area resorts", for instance, long before you see individual signs for each of the resorts in the EPCOT area.
Even being a WDW veteran, I make a wrong turn at least once a trip. Not to worry, though. I'm always able to turn back around within 1/2 mile or so. Once you've been there a day or so, it becomes a lot easier.
A GPS navigation system, or even Google Maps on a smartphone, can greatly alleviate the stress of driving around WDW.