I think Walter's advice for long sleeves and a head net is a good one.

Mosquitoes are normally just a minor nuisance, mostly in the evening, here in Paradise Valley on the Yellowstone, and they are usually mostly gone by about mid-to-late July. (This year might be an exception, but I don't think they'll be THAT bad in most places here.)

I'm sure it will be quite a different story elsewhere.