I’m loosely following a plan because I do most of my riding outside. What I do ( and don’t know if it’s correct) is find a workout which is as close as I can to the outside ride using a mixture of intensity, kJ’s, Time and TSS trying to match the energy system I’ve been stressing on the ride I then associate that workout with the the ride. If it’s a long ride with lots of coasting which I can’t match I pick the best hour or 1 1/2 hrs or whatever and just do the same with that section. ie if I do some hills or efforts at threshold during a long endurance ride I’ll pick that bit and use that. I’d be interested to see if I’m wasting my time however.