I originally ran this route when it was part of the official 2011 Lake Geneva Marathon race day program. It was called the Euro Marathon, for reasons unknown to me. Perhaps, all European marathons are a few miles short and run through people's backyards? 2011 was pre-GPS watch for both myself and the guy who won (his time, I believe 2:18:xx was much, but would be a supported effort).
I've tried to hit this route at least 1x per year since, but haven't run it hard since that first race day. I run the route clockwise, starting in Elm Park (library park) in Lake Geneva, heading East then South towards Big Foot Beach, then continuing to Fontana, Williams Bay, and finally back to Lake Geneva, as that was the original race route back in the day! Today, I planned on setting a baseline solo "hard" effort for the loop, then revisiting in the future as a fitness benchmark (with the future goal to break his 2:18). My plan was to run "right at or a little above high end aerobic" through Fontana (roughly mile 11), and then start cutting down from there. At some point between Williams Bay (15ish) and Lake Geneva I'd peg it if, I was feeling up to it.
I stuck to that plan, and ran a pretty steady cutdown (effort-wise), the final 10 miles. I was "one notch below all out racing" for the final 7 miles. Due to the nature of the terrain and all the twists and turns and stairs, it's tough to hold a steady pace, so perceived effort/HR is definitely to way pace for this loop.
I used 16oz of water with 1 scoop Sustainelite (120 cal) in a Salomon Soft Flask, Hoka Napali ATR on my feet - RIP :( , Swiftwick Aspire socks, and a Nathan VaporKrar waist belt for my soft flask. It was in the low 40s (F) throughout, which is just about perfect in my book!