When out with "backpacking" amount of pack and gear, I am in the same "camp" with Sam06. I have an Uncle Mike's with thumb snap on the pack waist belt. I also pack in an OWB Bianchi with thumb snap for arrival at destination when the big pack comes off.
Open carry is not much of an issue where I backpack in. This is usually after miles of boat ride, or snowmobile in, before backpacking begins. Don't think that the moose and bears really care between OC and CC.
For lighter trips, just the same Bianchi OWB with thumb snap, with a fanny pack for other essentials. My favorite hiking fanny pack also has shoulder straps, which tends to take the "bind" off of the holster.
Can't say enough about thumb snaps on hiking holsters. I have known several folks who have carried out in the bush without good retention, and had to backtrack to find just where their handgun fell out, and one guy who never did find his .44 mag.