I can't believe courses support the 15 minute tee time interval, unless they are forced to do it. Their tendency is to cram more people in rather than fewer... it's about filling the course and maximizing revenue. Not that I'm complaining...
Back in the day I could hit the ball a mile! Played near a scratch handicap. Also walked and carried a lightweight stand bag for many year despite an ACL reconstruction on my right knee, and MCL sprain in my left, various and sundry ankle breaks and sprains, and a left shoulder separation. But, after some time, my knees informed me that they no longer liked that!
So, I bought a pull cart. Played that way for quite a few years, until my knees started talking to me again! I fought against it for years until a 9 hole round of league golf would have me in pain for much of the week made me decide to ride in a cart!
You have to deal with reality!