Years ago I put out my 21 part multi, 15 Miles on the Erie Canal - A biking cache
I had fun putting it out, but less fun maintaining all the waypoints over the years. I eventually changed it from 21 parts to under 10, before finally archiving it.
I have redone this as an Adventure Lab: 15 Miles on the Erie Canal. When you complete this Adventure Lab, you will given the coordinates to this bonus cache as well as a hint. Make sure to look at the journal, as sometimes it seems completion of the lab doesn't show the last journal entry, so you might have to go back and look at the last journal entry.
Posted coordinates are one possible parking location, not necessarily the closest one. Though likely you have parked at the beginning of the Adventure Lab and I've made this bonus easily accessible without going much out of your way if you're still on your bike.
Terrain and attributes based on what is required to get the coordinates to this bonus.