Carl,
I was just thinking some more. (dangerous, I know) To motivate you do you need to set goals that compare to other people, or against yourself?

I, personally, can get a huge thrill out of tracking my time/ avg speed for a ride and always trying to do better. I am also getting into some group rides that have this same thrill, but you get to "compete" against other people. Maybe that will do it for you. Try some group rides. Some of the advanced people will be happy to drop you and give you something to work for.