The answer to the last question is to get in a group (again!!) and gig as much as you can. You'll sure end up learning those songs. If you have time to work really hard, use it for cleanup. Same if you jam a lot on a large repertoire. But face it, you haven't been playing since your teens, and you can't make that up in terms of repertoire in a very short time, not when you also have a day job and otherwise busy life.
As for a gradation of difficulty, go ahead and grade them for difficulty if that helps. Clear playing at high speed is difficult, as are correct and good-sounding executions of all sorts of licks. There is no standard progression. Just play what you know, and discern for yourself what you find hard. You can play any song an easier or a harder way, your choice. But if you’re working on tabs of other people’s breaks, you can judge what’s easy or hard.
Now, what is "cleanup"? That's my term for eliminating flaws in your playing. Not just some, but all, if you are really serious about playing. If you can't play a certain piece perfectly at the required speed, then you can constructively occupy lots of practice hours. The Loop Exercise Method I taught at the camp you attended (which can be found on this site under The Doc’s Prescriptions under Instructional), is my most streamlined method of conquering technical or memorization problems.
I have often pushed one hand or the other to pain, trying to conquer physical limitations on what I’m trying to play. When I hit pain, I stop that move and work on something that might give pain to the other hand. Then switch again later.
I keep a list of up to 10 things that are the highest priority for me to work on. I can soon enough start crossing things off the list, but then of course I always add, too!
I hope all this helps, Paul. Definitely part of what will settle you about this is to accept that wants are not needs, and that if you really do want big improvements enough to put in the time, they will start happening.
But most important of all -- Find some people to play with regularly! And have fun!
Pete