Question about cross training with a strained soleus

Last weekend I strained my soleus six miles into a half marathon. I hobbled jogged-walked the last 7. It was extremely painful for the first few days and I followed R.I.C.E. treatment guidelines. I went to the doctor Tuesday and he just said to take it easy (about what I expected) but he said I can cross train as long as it doesn't hurt. I have been swimming and/or biking over the past few days hoping to keep my endurance. Swimming doesn't hurt it at all and biking doesn't exactly hurt it. When I'm on the bike I can feel the strained muscle but it is not painful, it almost feels like a crunching. That's the best way I can think to describe it. So if I can feel the strained muscle while I'm exercising (even if it doesn't hurt), from your experience or knowledge, is it likely that I am hindering or regressing the healing progress? I would like to keep my endurance but I also want to get back out there running as soon as possible.