I got the holes cut in the belly pan today, I still need to do some sanding on the holes to clean them up. I then laid out where to cut the front of the pan to clear the landing gear. Once I had everything laid out, I cut the opening with my razor saw. I cut as far as I could with it and then I switched over to my hobby knife and packaging knife for the area's I couldn't cut with the razor saw.
This works really well and this is the process I will be using to cut out my elevator, rudder, and ailerons since I don't have a bandsaw big enough to do it, although I have been eyeing the Grizzly 14" bandsaw.