Most will say walk the course if you can to take it all in. I will say walk if you normally do or can walk 18 easily. I played last June and decided to walk. I never walk anymore. I used to walk 36-54 holes a week, but haven't walked 18 pushing or carrying a bag in 10 years.
When I play a casual round with friends every few weeks, I get the feeling around hole 14-15 where I wish it wasn't almost over. That is at a course I could play any day of the week, any week.
About hole 13-14 of Torrey Pines South, a once in a lifetime round on a top 100 course, I was ready for it to be over. The FRONT of my lower legs were even cramping up. I cramped up in my downswing on 17 tee. The terrain isn't terribly severe, but there is A LOT of up and down between greens and the next tee. I drove down from Long Beach, and on the drive back I was cramping up in gridlock traffic.
It's a beatiful place and every golfer should do it if you have the chance, but take a cart if needed and don't miss out on the last few holes like me because I could hardly stand up, let alone make a decent swing.