Firstly, don't stretch. Its useless unless after a fracture.
Secondly, to start your rehab work you'll need to mobilise your foot and ankle within pain free ranges which you can do as much as you want as long as it's pain free - basically just flex and extend it. This gently reintroduces load.
As pain allows you can start seated heel raises and add weight into it as you feel comfortable by using your hands to apply pressure. Then you can progress to standing heel raises on both legs, adding weight in as you feel comfortable, then progress to single leg heel raises +/- weight, then progress onto plyometric exercises such as jumping and hopping on the sport.
That's just for Gastrocnemius, apart from the seated heel raises. It's important not to forget Soleus too, by surface area its one of the biggest muscles in our body and provides the majority of our propulsion during walking and running. A solues squat is really good for this. Basically stand with your back against a wall and slide down it until you're in a squat position, then go up onto your toes whilst maintaining the squat and down. Keep yourself in the squat position whilst completing your repetitions. It's a great glute, quad and solues compound exercise. Again add weight in as and when you feel comfortable.
You can add eccentric heel drops off a step in as well, double then single leg, to go for the full shabang with your rehab.
It's really important to work to fatigue too, otherwise muscle strengthening won't be as efficient. It doesn't matter how many reps it takes or how much weight you're holding the important thing is to work until you get that burning achey feeling.
Return to running - intervals are exactly what you need to be doing but not full paces ones. Something like 30 second light jog and 30 second walk, then building up the time and intervals before eventually reducing the intervals with increased intensity until you're back to doing what you normally do.
The strengthening work should all take approx 3-4 weeks, possibly longer without constant monitoring. The running 5-6 weeks and it's ok to start when pain free.