David, you don't have to pay for any of the training packages. You just have to "be a member" of TrainerRoad (either monthly or yearly), and you get access to a whole suite of programs.
If you are going to start now, Ratz is probably going to put you on riding in your "aerobic" (180-age=HR) for awhile. Probably have you do an easy 8 or 20 minute FTP test first (There is already a program made for that - look back up the thread and I think he listed it.), then just basic aerobic riding for a block of time depending where you are at in your aerobic fitness. Seems like it would be easy, but it is not! I'm not sure if you even follow any pre-build programs for this.
All I did was "create" a simple program (with TrainerRoad's "Workout Creator" - also free). Just make one with a simple warmup and then 90-120 minutes of a constant wattage. If you hR ever goes above its range, then all you have to do is click the "down" arrow on the "%" field to bring the wattage down until your HR comes down.