While I don't want to see Yosemite or Grand Canyon or many other wonderful sites be developed, I believe it should be up to the States to decide what to do with their land.
If the Fedgov got out of the business of controlling/owning land tomorrow and handed over Fed forests/parks/monuments/land to the States, there would still be plenty of States and municipal govs that would preserve those areas. If Arizona actually owned the Grand Canyon, do you really think anyone would allow developers to build anything down in the Canyon? Of course not.
As an aside, what is your opinion of clinton declaring a national park (monument?) area in Utah that eliminated all mining for clean coal? (Riady payback) Shouldn't Utah have had the say in that? And what about obambi instituting a drilling ban for no good reason that has killed thousands of jobs? It goes on and on, not to mention the United Nations declaring some of our national areas as "Heritage Sites". You okay with that? I'm not.
PS. Do a Google search for federal owned land. You will be surprised how much it owns or controls. BTW, the EPA has become an obscenity to private property. It has grown way past its original purpose. I say downsize that to about 20%. I don't say eliminate it because we should have some Fed oversight on our environment. Sure I'm going to catch hell from the hard core Constitutionalists on that one.
As ridiculous as I thought a lot of environmental regualtion in my younger years, I have come to appreciate breathable air (and from Deleware to NJ to somewhere west of Gary IN the air was not breathable) and clean water for recreation (the Charles River in Boston, the Potomac in DC, SF Bay, Cheasapeake Bay) and fishing. I would argue that there is nothing conservative in a free market in poisoning ourselves.
I would also agree that USG should divest itself of a lot of BLM land. I would draw the line firmly at National Parks, however. Conservatism will fail if conservatives propose to divest its national parks. Only a few of the hillucinatory branch of libertarians would be willing to die on that battlefield.