"and have definitely noticed an increasing non-elasticity to the joints as I get older. The biggest issue has been recovery. I am still having difficulty in identifying the ideal train / recovery cycle, both in the short term (i.e. weekly) and the longer-term (i.e. 3 month cycles)."
I've been in the process of learning that the hard way the past 2 years, David. I'm reluctantly coming to the conclusion that, in my case at least, it is better to error on the side of caution and hope that the result is still "good enough to get the job done". I'll know by the end of this season.
"Oh, and I am on a strength cycle and am NOT combining this with interval cardio workouts. That would probably kill me."
I've got a friend, a genetically gifted 57 year old woman, who has been combining strength and cardio, both interval and endurance, for the past 3 years in preparation for high altitude climbs. She has finally reached a level where she is starting to get into trouble. We have been having a running, sometimes heated, conversation for several months now about whether it is time to start thinking about "good enough to get the job done". It is extremely difficult mentally to back off when you have a gift and are highly motivated to exploit it to the max in pursuit of lofty goals; it has led to a lot of broken dreams down through the years.
It sounds to me like you have got that figured out and are exercising restraint. I commend you. The yin of restraint does not often tame the yang of desire.