Bac -

Some areas are easy. Almost all of Nevada is BLM land. After you pass the national forest signs, most of the land is national forest - certainly unfenced. Still, it is best to have national forest maps or BLM maps. A secret - if you go by the national forest office and ask for travel plans - those are free. Not as nice as national forest maps - just two color - but you can identify private and public lands - plus you have a detailed map for your touring/hiking.

As for the high country. I mentioned that Canadian parks allow you to bike on certain forest roads. A mountain bike is best, although you could do it on a tourer with hefty tires and some walking. In U.S. parks and national forests, I will walk my bike a short to moderate distance on trails that are NOT in wilderness. I never take my bike into wilderness areas.

Finally, unlike some, I am perfectly willing to lock my bike at the trailhead, put my panniers in bear boxes or hang them, then put on a backpack and hike in. That's why I tour with a midweight pack across the back rack. It gives me lots of hike/bike flexibility.