Good news. The roof is fixed, and I'm not broken.
I ended up using a different approach than I had planned. I started out by setting up the extension ladder on the 1st floor roof area (with 3-4' of ladder above the roof line) and just practiced getting on and off the roof a few times. It is interesting that EddieWalker indicates he is more comfortable with about one foot of ladder above the roof. That is the way I had been doing it, and I didn't know 3-4' was considered the norm. For me, this was a huge improvement. It was the first time that I didn't even feel awkward getting off the roof.
Then I tried setting up the ladder from ground level to the 2nd floor roof. When I extend my 24' ladder all the way, there was only about 2' above the gutter. I climbed up to the gutter, and the ladder step I would have used to step onto the roof has a warning saying you should not step on or above this step or you may loose your balance and fall. (I'm briefly reminded of the Simpsons episode where Homer says, "You see Lisa, because of me, they have a warning!") I decided this was not good. I considered buying a longer ladder, which costs over $300. But truth be told, I don't even like standing on a ladder that high. Even if I bought a longer ladder, I don't think I would have been relaxed when I step on and off of it.
I ended up using two ladders to get to 2nd floor, like this.
From a physical standpoint, I suspect this approach is actually less safe than a direct approach to the 2nd floor. But for some reason, my mind is able to accept this approach better, and both of the ladders actually felt quite stable to me.
Before posting here, I did a fair amout of Google searching. I found lots of general ladder safety pages, but I couldn't find information about getting on and off a roof. I wasn't expecting to get so many responses, and this has been a good learning experience for me. I appreciate all the feedback.