I was curious about this route for a while, having so many different surfaces and being so flat/downhill and the satisfaction of going from the lake to the sea. This definitely favors a fast road runner but there's enough singletrack to keep it interesting for a trail runner (plus the horrid railroad section).
I decided to go for it in early April and overall the terrain and temps were good, although there was some snow still lingering at the north end but I wasn't slowed down much. Walked in to the beach on Sebago Lake with my girlfriend Brianna and set off south, carrying all of my water and nutrition and received no aid or support along the way. The only minor navigational error (maybe lost 10 seconds) was missing the turn onto Bramblewood Drive, otherwise relied on the scouting I did of most of the suburban turns and followed the Sebago to the Sea trail signs which were decently well placed, as well as checking Gaia a few times to be sure. Jogged it in on the Eastern Prom with failing legs and jumped into the ocean to finish it off. The hardest part of this was the ~4mi railroad section where the side was chunky rock/at a weird angle and running on the railroad ties down the center was nauseating, plus felt like I was either under or overstriding the whole time. Would love to see a marathoner push this down closer to 3 hours. A road shoe can definitely be used on this (I used the original New Balance RC Elite which had decent outsole grip/energy return) but with the amount of singletrack, although mostly non-technical, I think the TNF Summit Pro and Adidas Speed Ultra would be perfect.
Note: this was written on 5/23/24. My Strava description was written the day of the effort. I meant to submit this FKT much sooner but life got busy and ended up putting it off and forgetting for many months.