There are different schools of thought when it comes to when to lift legs relative to hard/long runs, but the generally prevailing thought is to put your leg workout as close to and after the hard/long run and with maximum time between the next hard/long run.
Example schedules are:
Tuesday AM: workout (hard run)
Tuesday PM: legs lift
Wednesday AM: recovery run (could also be moved to Wednesday PM if needed)
Saturday AM: long run
Sunday AM: legs lift
Sunday PM: recovery run (can be thrown out if needed)
Monday AM: easy run
Another thing that I think is important to note here is that a legs lift day is going to look quite different when running this much than it would if you were doing legs day in a traditional strength-first program. Going really heavy on big lifts and then trying to run the next day is probably not going to work well. Also, highly controlled isometric exercises, even at an amount of weight that will turn zero heads, are going to contribute to the function of running really well.
Like all things, adaptation occurs and it gets easier with time and consistency.
Example schedules are:
Tuesday AM: workout (hard run)
Tuesday PM: legs lift
Wednesday AM: recovery run (could also be moved to Wednesday PM if needed)
Saturday AM: long run
Sunday AM: legs lift
Sunday PM: recovery run (can be thrown out if needed)
Monday AM: easy run
Another thing that I think is important to note here is that a legs lift day is going to look quite different when running this much than it would if you were doing legs day in a traditional strength-first program. Going really heavy on big lifts and then trying to run the next day is probably not going to work well. Also, highly controlled isometric exercises, even at an amount of weight that will turn zero heads, are going to contribute to the function of running really well.
Like all things, adaptation occurs and it gets easier with time and consistency.