I've been carrying a full-sized 1911 using just an IWB holster for years while backpacking (500+ miles last 2 years alone). Alternating positions is the key. When I really need to conceal, I clip it in just right of the belt buckle. At some point this generally becomes uncomfortable and I begin periodically alternating between a far more comfortable unclipped position (cinched in tight w/ belt) just in front of the right hip. This is less concealed, but with the backpack, straps, etc. it's still concealed. When it get's dark and/or concealment is not an issue, I can also clip it inside/under my pack's kidney strap for a total comfort/drying out. When the pack comes off, you can still switch to a standard position behind the hip. I use a DeSantis leather holster with an Uncle Mike's clip for easy manipulation. Perspiration can be an issue though - I carry a stainless gun.