do those low weight/high rep leg sessions. get plenty of stretching in before, during, after, then way after. make sure that any soreness will not interfere on your runs. i am always fighting my leg routine with my runs and bike as far as soreness is concerned. its a delicate balance. of course i have been doing high weight/low rep - but this must change.
if soreness creeps in, either lower your weight or reps or both. 1-2 days should be plenty for benefits. from your schedule, at least try to have a day off from both. either do weights once a week or combine one of your 2 sessions with a light run day for example