30-06 is 30 caliber, adapted by the US army in 1906, hence the 30-06 designation. started with the 1903 springfield rifle. If you played medal of honor, that's the sniper rifle. Same ammo used in the m1 garand, the 1917 springfield rifle, and the BAR - browning automatic rifle. When the round was developed, it was the era of trench warfare, so you had a bunch of guys shooting each other from 500-1000 yards away from holes in the ground.
So now you know the expected range out of these rounds the mosin nagant shown above uses a similar round, which has about 600-800 yards effective range, and i believe they're sighted in for 300 yards from factory.
The reason to keep a sidearm, such as a pistol, is so you have a backup incase of a malfunction, and a 250 lb pig is pissed off charging at you at 20 mph. For a sidearm (and you're right, you can't OWN a handgun, but you can shoot one), you want something with raw stopping power. a 9mm won't cut it, but a .45 caliber 1911 is something worth looking into as a backup for wild game. Personally, I don't hunt, but I believe in this case a revolver would be a better choice.
Why a revolver? Because if you can't get a jam in a revolver, and if you have a misfire, just pull the trigger again to rotate the drum. A semi-auto pistol is nice, but there's just too much margin for error in that situation
Scope is not overkill. Don't pay attention to people saying "oh, hunt it with a bow, at least give it a chance." Think of getting into a fight with someone that can beat the crap out of you in hand to hand combat. First thing I would do is kick the guy in the nuts, I don't care how low it is, I don't like getting hurt
Big5 has remington scoped rifles for 300-400 bucks on sale all the time.
http://preview.tinyurl.com/ywz7oa