I did a 60 mile commute for a while (round trip) and had opportunities for 98 mile round-trip commutes on certain days. Not much in the way of hills/climbing, but I am a climber - so there's "hills" and then there's "hills," for all of us. It was a MASSIVE time commitment, but it was fantastic training. Due to the massive amount of time, I was generally only able to make the full trek by bike a couple times a week... if you plain run out of time to get on the bike and ride in, you just plain run out of time - gotta get in the car.

But speaking of car, I also would occasionally drive in halfway and do the rest on the bike. Still a big time sucker, because driving also still takes time and a 30 mile drive is still a hell of a commute even by car, in the city. But a lot more doable. In fact, when my commute changed to a location over these here West Hills, I would generally drive all the way to the bottom of the hill and ride up and over. Still netted me about 4000' of gain and took about the same amount of time as doing the full flat ride in (1:20-1:30 each way), but HO LEE FUK what a great training week.