Here's my experiences. For femurs, PT is very important. Stretching and strengthening so many large muscles around your hips and femurs, and restoring your walking gait, are crucial.
I'm in the middle of lengthening my tibias and I see PT requirements to be considerably less than femurs. With tibia PT, you are primarily focused on stretching your calves to fight ballerina foot (i.e. restore dorsiflexion angle) and the muscles around your knees. Also strengthen the muscles and bones from your knees and below. Once I'm done tibia lengthening, I probably only need a PT to restore my dorsiflexion angle as much as possible and strengthen to consolidate faster. This will probably be one month at most after lengthening is done. After that I should be consolidated enough to use the slanted calf stretching board to stretch my calves. No need to have a PT restore your walking gait because the muscles around my hips and upper legs were hardly affected.