I most usually always have my bow at hand when i'm in my treestand. I use a lone wolf climber that has the built in bow holder but it's always too much of a pain to get my bow out when I see a deer coming in. When I ground hunt i'm either stalking with bow in hand or usually sit the cam on my boot and hold the wheel with my hand to give my arm some sort of a break. Whatever you do, you just have to be ready to get up and beready to draw before the deer get to you. It's a lot harder when they're right on top of you or you have several sets of eyes watching you.

As far as not seeing the deer before they're right on you. You might try a little different stand placement and try to anticipate where the deer might show up in relation to that. I don't know what kind of land you hunt, but it does make it very difficult when you're hunting the thick stuff or when there's ridges or benches where the deer can just pop up out of no where. I always try to keep scanning the area constantly for any kind of movement and try to listen for any noise at all, especially when it's raining or the ground is wet. It's amazing how something that big can sometimes sneak right up on you.