As a critical part of one of my pace of play improvement programs at a golf course near San Diego, I created a Pace Rating for the course. The course has a fairly short playing length (tee to green) of 6529 yards from the Blue Tees. However, as a course built to support a housing development over some hilly ground, it also sported an amazing total travel distance from greens to tees of an additional 5180 yards, or 2.9 miles! That's a 6.6 mile hike to play 18 holes. Maybe not "un-walkable" but not a lot of fun.
In fact, the very first time I played the course, when asked at check-in if I wanted a cart, I said,"No thanks, I like to walk." The guy behind the counter said, "OK, but you'll be the first to do it." I took the cart and was very glad I did.