Diane in particular…I am 55 also, with plenty of age-related nonsense going on, and all I can say is, don’t stop! Stopping is a downhill slide, a fast one. Take a break and get some rest, but go walk every single day no matter what. A few things that have helped me:
*diclofenac cream – the pill is really hard on the stomach, but the cream takes the edge off a complaining joint
*massage – it helps not only the muscle but also the joints, loosening up everything around the joint
*weight training – I hate it, it’s boring, and I feel silly doing it because I’m not very strong. But it really does help strengthen everything. Get a trainer if you haven’t done it before.
*yoga – the combination of stretching, strengthening and breathing is just perfect for getting all parts up and operational. The breathing and balancing practices really help me in sketchy areas, like scree, wet logs and rocks, etc.
*weight loss – I struggle with this and I’m not too overweight, but just enough that it makes life a little harder. I need to shed 20-30 pounds. Not sure if this affects you or not, but I find that while it can be a vanity thing, it’s also a huge part of getting out. Losing even 10 pounds makes the walking much easier, and the load on the feet and knees much less. But it’s  hard to eat less! I eat a very healthy diet, just too much.
I haven’t had the foot problems you’ve had. I would bet the sole problem is due to a too large shoe, with your foot sliding around? Rather than too small, as Roger suggests. That’s my take on it anyway, but I’m no expert. But anything moving inside your shoe as you walk is going to get rubbed raw due to friction. I like a shoe to fit snug but not tight, with only the toes having a bit of extra room.
Getting older sucks, physically speaking at least. No sugar coating it. But it’s always so worth getting out there. I loved your videos especially since it’s  an area not too many folks walk. Don’t stop! Do whatever it takes to find a way.