Strength Training Structure Advice:

I've massively been neglecting strength training, which is leading to a few niggles. How do you guys structure strength training with your running program? Looking to do about 70-80mpw for my next block w/indoor bike cross training & I've noticed when i've gotten to 70+ mpw a couple time in the past, i felt really low energy the next week and wouldn't even get close to 50miles.

How would you do legs for example, and still have energy and not be too sore for the next training day? Would that be a back to back easy day? Or Keep hard days hard and do the strength training pm after a hard am session?

Really grateful for any advice you guys have on this. I know it's not a "one rule fits all" type thing and trial by error could be the only way to really find it out. Would love to hear what ways you guys breakdown training.