Complex sentence: One example of roadless area conservation is Alaska's Denali National Park, which is prized for its expansive roadless area; there is only one 90-mile access road into the park, and only official vehicles are permitted after 30 miles.
Split into simpler sentences: One example of roadless area conservation is Alaska's Denali National Park, which is prized for its expansive roadless area. There is but one 90-mile access road into the park; only official vehicles are permitted after 30 miles.