I'll start by saying that I really like my Gary Fisher Wahoo with rim brakes and don't want to invest in another bike right now. I alternate between trails without my wife and bike paths with my wife. So I've been changing tires and tubes from trail knobbies to slicks and back again, which gets tiring, or riding bike paths on trail tires which is less than satisfying. Can I get a second wheelset for slicks and have the bike set up for both wheelsets without adjusting anything? Am I looking at any trouble with this idea? Any setup tips? Do I need to closely match the specs on my current wheels to the new wheels?
If the rim OD is exactly the same or you run your brakes loose enough for the wider rim, yes, everything will swap without any changes. Actually that also assumes you run the same cassette or one near it.
I used to do this foolishness on my wife's hybrid. Then she got a road bike and I left some cyclocross semi-knobbies on the hybrid. Now she's adding a MTB to the stable. I would suggest you go that route.