****[S]ince some injuries have cleared up, I continue.
OK, we're relatively the same age. When I say some injuries have cleared up, I tend to mean they've progressed to the point of being asymptomatic. So, when you say they've cleared up, do you still have some concern about reinjury to any of these old injuries?
If it were me, this information is important in assessing what a realistic training program would look like.
So how do I aproach this situation so that I don't feel like some suburban slob with nothing better to do evenings?
I think the following is a great place to strart, as you don't come across that way at all:
I need to figure out how to plan my training as I feel I'm being urged to "move up" with my practice.
I'm 52 and I need to know if my body will be able to support my advancement.
Especially Ukemi. I feel the responsibility to provide others with comparable ukemi to allow them to practice effectively.
I have the highest respect for my sensei and the other dan students and feel I would like to talk about this plan aside from the 10 minutes between classes.
I think your concerns are perfectly legitimate, and the way you are thinking about addressing them seems sound, FWIW.
Also in the realm of "FWIW," your ukemi skills probably will continue to get better with time, so you can take better ukemi with less effort as you get older.
At the same time, maybe think about what kinds of other training might help your conditioning for ukemi as your dojo practices it, as that also helps you use less effort.
That could include training ukemi skills, of course. But, some people as they grow older do more weapons work.
If the choice came down to doing another body-arts class when I already feel beat up, or doing a weapons class instead, I'm probably better off in the long run, and in terms of my body-arts' training, to do the weapons class.
Hope that's of some use.