RE: Slugs
Here in upstate NY I was forced to hunt with slugs for years. As for what you would need to set up your shotgun for slugs it really depends on what kind of slugs you want to shoot. If you are going to stick with just your plain smooth bore barrel all you have to do is make sure you have an improved cylinder choke tube in (in theory you can fit a slug through a modified but any tighter then that will create problems, I'd go with the IC though) and you will be ready to go. If you want to shoot some of the fancier, and much more expensive, new slugs out there you might want to invest in a rifled barrel, or at least a rifled choke tube. These slugs tend to be faster and more accurate downrange then the older style foster slugs. I used to shoot an 870 with a Hastings rifled barrel and Remington Copper Solids that was real accurate.
Although you could prob shoot just a bead if you were going to shoot at fairly close range I would at least get some type of iron sights on it. Even better would be to get a decent scope. The way I look at it shotguns w/ slugs are naturally less accurate then a rifle so any gain in precision in aiming (the scope) is a plus. You want to make sure the scope is made for shotguns specifically however, the recoil of a shotgun will blow apart most rifle scopes.
The one thing about shotgun slugs is that they usually have quite a bit of recoil, and if recoil bothers you it might be a good idea to try a 20 gauge, or some of the reduced recoil slugs Remington makes now. 20 gauge slugs still pack a powerful punch and some people prefer them over the 12 gauge. But that is a personal choice. All in all a shotgun slug at close range is some pretty powerful medicine for all North American big game, especially deer. The biggest shortcoming is their range and accuracy, but due to recent advances in slug technology even that is changing, and some people on here have claimed to make clean kills out past the 200 yard mark. (as a disclaimer I don't know if these 200 yard claims are true or not, you should establish your own maximum range). I realize that might of been more information then you were looking for but I hope it helps, if you have any other questions feel free to ask, their are a lot of knowledgeable people here