A one of those with the potential to "raise a ruckus"
(as Izdaari put it), I'll weigh in with having no secular or religious problem with either the proposed Muslim camp
or even a Christian camp under similar circumstances.
According to the Army Corps of Engineers'
recreation bit they operate more than 2,500 sites making them the nation's largest provider of outdoor recreation. I would imagine that if they're considering leasing a site to a Muslim organization that the currently, or have in the past, leased property to Christian or possibly Jewish organizations as well.
I can't say I'm a big fan of just giving away public land
(for an annual fee of $1) while these groups may be able to turn a hefty profit, but on the other hand I think most of them probably provide good public services for children and others.
I think the only ruckus could come if this Muslim organization or any others were denied the land on the basis of their religion while any Christian organizations operating were allowed to continue. It doesn't sound like they will be denied, though, even in spite of misguided fears of terrorism.