Parents had a place on Fisher Lake until about six yrs ago, so I used to ride Iron Cty, every year, for 10 years.
I wouldn't recomment Mercer, because it can be hit and miss on snow depth from year to year.
Incredible difference between Mercer, Pine Lake, and Hurley. Fisher Lake was 10.5 miles northeast of Mercer, and there was significantly more snow there than Mercer.
The line is pretty much Pine lake (trail 17) and north, for excellent snow - most winters.
You can do some serious riding off trail, just about anywhere in the northern 1/3 of Iron Cty. That would be about the northern most 10 -15 miles.
Fisher Lake and north had incredible snow for a few years there, in 1996 - 1997.
One year the exhaust pipe on the furnace was snowed shut - probably 4 ft. high, the shed collapsed from the weight, and the banks along Fisher Lake rd. were 10 ft high.
I was travelling west of Hurley on trail 2, riding alone, about six miles out of town, when i decided to turn around - off trail.
Riding a 1994 Thundercat, this was a BIG mistake. Buried the sled up to the windshield. And that thing epitomized "pig" when it came to weighty boat anchors.
It wasn't moving without 3-4 hours work alone. Fortunately a group of ten came along in about 15 minutes and go me out. I learned a lesson that day.