I am also an old biker and If you could take the old U.S. 66 before 1968 it would be well worth the trip. Today you can only go on parts of it but it is nothing like it used to be. There are ways to cover the old route but it would take some planning. Get one of the travel guides to the historic Route 66 and make a plan. Do it in the summer or fall for the best weather. Good luck.
(see my HUB "COMING OF AGE - Route 66 ")