Normally when doing endurance training, once you get into it your body should really only need 24hrs to recover.
The problem with doing the strength training is that it can take longer for the body to recover. It all depends on what intensity you are working at.
It's good that you are following a modified Pavel routine for your strength. You can also do similar for your endurance. The main thing to make sure is that you don't overtrain. If you stop making gains then you can take a few days off. Remember as well as the cycle programme you are following for your lifts, take it on to your endurance also. This is where it is important to record all your training activities. Each exercise should be a cycle of itself, so when you fail to make gains in a certain exercise you take a few days off from that exercise, not all exercises.
Hope that has helped.
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