How can i prepare my body (i'm 68) for a long 9 hour flight and 15 days of walking tours when i have spinal stenosis. when i overdo walking, i suffer?

Spinal stenosis: That is a difficult task. Lumbar spinal stenosis causes back and leg pain with walking (neurogenic claudication). Fortunately most walking tours have frequent stops to discuss what you are viewing. Take a cane that folds out into a small stool so you can sit and flex your back to decompress the pinched nerves. Do stretches in the morning and evening. Add ice to the back at night.

Start Training Now: Start with core strengthening exercises, also see if you can tolerate increased sitting and walking times. without pain. lastly you mint want to get an injections like epidural steroid or even facet joint injections to help with the pain while you are gone.