Hey Terry! What a cool way to celebrate your birthday! I always love your videos (I just don’t have the time and patience, as I’m sure you have to put in a lot of work both filming and then editing).
The saddle time sounds a little daunting for me, but it’s a great goal! Congratulations! (I just did my first ride with 100mm cranks on my 36er and it went well, see http://www.unicyclist.com/forums/showpost.php?p=1644093&postcount=16)
And as always, you’ve found a great way to stay young! You’ve got a good head start on me, but I expect to be just as “crazy” for quite some time! As you already know, if you stay fit, age is almost entirely in your head (e.g. people who are like 30 who say they’re too old for this or that is just crazy, as far as I’m concerned). When I tell people I learned to unicylce in my mid thirties they are always surprized.