If you have access to weights, go back to using weight. You want to do the same movements; i.e. squat, benchpress but no reason not to use weights. PEM is really good for people who don't have access to a weight room.
2-3x a week should be about the max for weight or even PEM. A little soreness is ok, as a leatherneck I'm sure you know the difference between being sore and being hurt.
You don't need to work each of the lifts to muscle failure, you want to be able to steadily increase the weight.
Don't be afraid to rest though, if you're really sore, go do something else. A relaxing swim, a hike, something active but not requiring a lot of exertion; i.e. slow movement.
"Go For Broke"
Fat Kine-230/24% @ 6'2"