In addition to scrunches and rolling the ankles there are a couple others you should be doing:
legs together out straight feet pointing with big toes touching, try to make the soles face eachother. This should result in a cramping feeling, which you then back off, concentrate on relxation of the tightness, and then repeat.
feet pointing, write the alphabet in the carpet with your big toe
towel curls: scrunch a towel toward you with your feet, scrunch it to the sides, place weight on the towel for more resistance.
The counter stretch for these exersizes are runners stretch and kneeling with bottom on heels, balls of feet on floor, toes curled under, inching the knees forward for a gentle release (should feel good after scrunching).
Some doctors believe pf to be a degenerative disease. I think that is a gross simplification, but it does point to the fact that strengthening is necessary, and atrophy could be a complicating factor in chronic cases, for obvious reasons. There is a definite downside to rest.
Another exersize is calf-raises on a stair, but probably should only be done if there is a railing to use arm support to take weight off and control the resistance so that it is very slight. Full weighted calf raises could be problematic.
warmth before and ice after exersize is good, but this varies with individuals long term experiences it seems.