Hey @huges84 ,
This method that @alexfthenakis mentioned is the way I usually do it.
I often ride ~30-60 minutes out to where I’m going to do my workout and I just wait until I get to that starting point to then load the workout up onto my head unit.
Then, I’ll do the workout until it’s finished and ride on home.
At this time, PLs won’t be affected by the extra riding around your workout. Your PLs for the workout itself will still be accounted for, though, which means you PLs for the zone of the workout will still be accurate.