Hi Bill --- good question. We're going to be working on having the site answer questions like this early next year. Two lesson series that I think will give you a solid foundation are:
How Long Blues
Blues After Hours
The tempo of both tunes is nice and they introduce a lot of concepts Duke gets into in other lessons. After that, you may want to check out
Take a Little Walk with Me
That's Alright
I hope that helps and enjoy Duke.