I agree with those who allow this ride on any day during the year, whether this is calendar year, year following the b'day, etc., I have no idea, but I'm flexible. My birthday is in November which means I can most certainly ride on/or near my actual birth day. I'm still working so I need to deal with my work schedule, at least for this year.
Around here the big problem is the amount of climbing involved in an enjoyable 65+ mile ride. The valley is loaded with traffic, stop lights and stop signs.
I will say that I think the ride should essentially be a single loop and not repetitions of, let's say, a 10 mile loop, but that's just me. When your 60+ riding your age is a big accomplishment no matter how you do it.