I'd say that it depends where you are hunting. There can be wide range of temperatures based on your location. I would google the average temp for the nearest city to your hunt. If you will be hunting high on a mountain, I believe you can expect the temp to be 3-4degrees cooler per 1000 feet of elevation. I would definately bring some sort of tent; like cowboy said, it could rain quite a bit. As for the sleeping bag: I would think you could get away with a 20 degree bag. Again, depends on overnight temps. Just don't under-do it. I have a 0 deree bag that I use for just about all of my hunts because its lighter weight than my 20 degree bag. I can unzip it, if too warm, but if your bag is too cold you're just miserable.
A tip: When its cold outside, put a handwarmer in a sock and throw it in the bottom of your bag. Its a lifesaver.