Have you already purchased a daypack? The only method that's worked for me is to use a daypack with a dedicated pouch for the camera. It doesn't have to be a made-for-cameras bag per se, but having a dedicated, zippered pocket for the camera is huge. It's especially helpful if you can reach behind you and unzip it and remove the camera with one hand, without having to shuffle the bag around your shoulders. I use the LowePro Streamline Sling which is great for this, though the non-camera storage area can be a bit stingy.
If you already have a bag, just put an ND filter (or whatever) on your lens to protect it and chuck the whole thing in the bag and enjoy your trip. If you make too much of a fuss about getting your camera out and putting it back in, you'll end up skipping shots or using your smartphone just because of the hassle. You'd be better off keeping the camera in a jacket pocket. If there's anything in your bag that's harmful enough to scratch/dent your camera, you should consider protecting/isolating/moving the offending item so it doesn't wreck anything else