So, for whatever reason I had been leaving a routine stretch out of my recent runs with the 5Fingers. Basically standing up you cross one leg in front of the other and bend at the waist.
Now I can't isolate whether it was the return of this stretch to my routine or just more time with the 5Fingers, but I had a largely calf stress free run today. I coasted back into the office feeling great and could have run farther, but thought better of it and headed back inside.
Anyway, I will probably toss in another run this weekend --- maybe two. I'll keep you posted on how it goes. Hopefully I'll be able to start extending my runs to farther than 4 miles.