Let me add to what the others have said so far to not let yourself go to pot. In 2005 and 2006 I was registered to run St. George and both years had to pull out due to a strained (or pulled) calf - one year I managed strain both, one right after the other
Unlike you, where you are trying to get some good crosstraining in to keep up your fitness, I just turned into a couch potato. I would just try to find any activities you can that will give you a good cardio workout while also working the legs. Biking, swimming, aquajogging, etc. Whatever is going to be low/no impact while also allowing you to let your soleus heal. Have faith, you WILL get better . . .