Private or public property? It can make a difference on both baiting and what kind of treestand to use. Some people use climbing tree-stands (you carry it with you each time and climb the tree, usually on public land or where it might be stolen if left there semi-permanently) and some people use ladder type tree-stands that are semi-permanently attached to a tree, usually on private property where you are confident the stand won't be stolen. Prices obviously vary depending on which stand you buy.
Your aiming point question (can be a little different from a ballistics question) would depend on what angle you're shooting at. Basically, envision if your aiming point will allow the bullet to travel completely through the heart and lungs area or not.
For instance, if you're shooting horizontally at the side of an animal, you're aiming for the side of heart/lungs. If you shoot at a 45 degree angle, you aim pretty close to the same point and maybe just a smidge higher to make sure your bullet is going to fully penetrate the heart/lungs as it passes through the animal's body. If you're almost directly above the animal, you would have to shift the aiming point higher on the animal's body so that your bullet is passing through that same heart/lungs.
Your ballistics question would depend upon the total distance you're shooting and the angle although if you're shooting less than 100 yards, it isn't going to make much difference. For instance, say you're shooting 100 yards at a 45 degree downhill angle from your treestand. Using the cosign for a 45 degree angle (.70), your bullet would be traveling the equivalent of 70 yards horizontally. With your rifle sighted in at 70 yards, you would be dead on. And even if you saw the same buck while standing on the ground with a horizontal shot at 100 yards, you likely wouldn't adjust your point of aim anyway.
http://www.rifleshootermag.com/netwo...ow-angle-shot/
http://www.chuckhawks.com/shooting_uphill.htm
There's a whole lot more questions to answer in order to give you dialed in advice on this stuff. I'm more of a still hunter who occasionally uses a ground blind. I've used tree stands before but they were ladder tree stands permanently installed on private property. They are nice and offer some obvious advantages (height, less of your smell in the woods, etc.) but you also end up having to sit still for hours at a time which works for some people and not so well for others. There are a lot of other guys on this forum who are much more experienced in tree stands and will likely have a whole lot more pointers for you.