Beautiful hike and well worth the miles, but there are some ailments!
First off, just an FYI, when you get to the pay station you DO NOT have to pay the day use fee! That’s only for the actual swimming and picnic area. When you drive through the campground, you’ll come to a trailhead and a big sign that says “trailhead parking, no fee”. It doesn’t say this at the pay station, which was a pain bc we ended up paying the fee!
You’ll actually start at the Badger Lake Trailhead and not the Fourmile one. Once you start, you’ll see a sign that will point you in the right direction. Throughout the rest, the hike is very poorly labeled. We got turned around multiple times and ended up on a portion of the PCT for a third of the hike (making us miss the top of the loop where a multitude of lakes and a canyon is). The PCT cut off will spit you back on the trail, but other than the trail head, none of the directional signs say Fourmile. So when you get to splits, make sure you check your GPS and go the right way. We ended up taking on almost 3 extra miles bc of this. There are also many fallen trees across the trail towards the last half, one pile so bad you have to leave the trail and trek around it to hop back on trail. This did not bother us, but may cause problems for others. Also, when you reach the end of the trail and try to go back to your cars... it’s super hard to find the trailhead again. Just hit the main road in the campground and walk back around. Save yourself the trouble we had of walking in circles trying to find the end trail where we had specifically started. Woo, that is all. Ps: bring deet.