"I don't always have 3-4 hours available for what I consider a decent ride/workout."
"Endurance for longer rides, especially into the constant infernal headwinds we get around here is a secondary goal for me at the moment. "

It's not worth starting a flame over this.

alanknm,
I think everyone has a problem with those long steep grades. I have been working on it for the past 3 years and am finally getting it. I have limited time like you - a full time job and a busy family life. My usual week is two training rides at 6AM before work, these are 17miles and two weekend rides, one will include hill work and the other distance.

medinism (Welcome - BTW) is using the same program I have been using this spring - seems to be a good program and is working for me as well. The shorter routines will make you feel like you did something if they are done right. However you are not bone tired at the end, I still put in a full days work. I usually don't get bone tired on rides anymore but I still get a good workout.

Hill repeats are good and help hill climbing endurance. However nothing beats finding a long grade (not stupid steep) and just do it.
A 3 to 6 mile hill of 1200' to 2500' rise is what I use.