The only issue with PBI is that you have to take I-95 to get there. MCO is 45 minutes while PBI is going to be a little over two hours from the Coca Beach area. That's a lot of extra roadway that sees a lot of accidents.

PBI is an easier airport to navigate, however having TSA Pre will save you up to 90 minutes in lines at MCO. The longest I've ever waited for TSA there with Pre was just under 20 minutes. That was an anomaly, it's usually no more than five.

As to all the walking, you can drop your wife and the kids off at the terminal entrance and they can wait while you go and return the car and come back over to meet them. There is no more walking in MCO than there is in PHL. If you are fine with PHL, you'll be fine with MCO. Plus you get to take a last monorail ride on the way to the airside terminal where the gate will be, which is something your kids might enjoy.