Interesting thing about mining claims: when the National Forests were created, the land rights to patented mining claims were gradfathered in. So it is not unusual to have a small group of claims that is completely surrounded by National Forest, accessable only by four wheel drive. Not only that, but the same goes for wilderness areas, areas set aside where not only can roads not be built, but no motor vehicles can be operated. I took a quick look at the Summit County (where Breck is) GIS website and saw that there are many isolated mining claims inside the national forest and a couple inside the wilderness area in the county. IF you had a cabin on a claim in a wilderness area, you'd not be able to drive to it. You'd have to take a horse or hike in. In the winter, that'd be snowshoeing or skiing in.

If you are in need of early history of the area, gimme a shout, there are a couple of excellent sources on Google Books.

I've never had a problem using my cell phone in Breckenridge, but I've not been in the backcounty there for many years. As long as the cabin had a view of the town, or the highway through town, she'd probably have some coverage.