Alright, thank you all for your responses to the last set of options--they've helped a lot in trying to figure out what exactly we should be looking at doing. I think we've got five options here that'll rock your world. They come in two basic types: City+Outside the city and City+City.

A word about City+Outside: Matt and I were talking about it and decided that long, multicity trips (in addition to being a bitch to plan and price) would just drive us batty because instead of relaxing (which is what vacation/travel's supposed to be about, yes?) we'd be worried and freaked out about getting where we were going and making sure to see a bunch of stuff and hit all the places we want and so forth. And there's been a wide enough response from people that we might end up getting a large group (6+ people) together. Which would be awesome, but would make a multi-city trip almost unimaginably difficult in a number of different ways. But the flip side of that is that with a larger number of people, the cooler/better it becomes to just hang out someplace.
So, we took that and ran with it and put together a couple of options that deal with seeing a major city for about 5 days then getting in a car (car rental rates are sane, it turns out) and driving to cabin/rental home and hanging there for a week. More about each of the individual options later, sure, but I just wanted you to understand the logic behind this decision. And if no one wants to do it, we won't do it--we'll pick one of the other options, but it could be remarkably awesome to get in both a metro area some chill/nature time as well. Also: plans of this stay-somewhere-the-whole-time kind save us money, as flying is expensive.

So, here are the current set of possibilities (with room, of course, for your suggestions as well):

A) Vancouver --> Cabin.
The most America-like part of Canada is easily British Columbia, and it's got the benifit of being amazingly gorgeous. Plus, it's north of everywhere, and hence cooler and more wooded. The downside to Vancouver is that cabin rentals are more expensive (in the neighborhood, maybe, of more like 50$/person/night rather than the 30$/p/n that I was hoping for). And if y'all's cool with that, then that's not a problem at all. Probably comes out to something like 900 or 1000 dollars/person, total, for structural costs (getting there, getting around there, sleeping).

B) Denver --> Estes Park or Jackson Hole
Denver is one of the coolest large cities in the western US, with a world class art museum, some fantastic botanical gardens and three worth-seeing micro-breweries. Oh, and the Coors brewery, whose tour I could lead, should something happen to our guide. The beer's not very good at Coors, but it is exceedingly free. Anyway, that's Denver.
Estes Park is just outside Rocky Mountain National Park. Estes Park itself is small, quaint, touristy kind place, but it's got enough interesting stuff to spend time in/at. The bonus here is that it's close enough to Rocky that you can spend the day in the park then come out and eat at some fairly good restaurants in Estes in the evening.
Jackson Hole, Wyoming (a day by car from Denver), is about the same. The town's about the same as Estes, but smaller and less costly/fancy. It's just outside the Grand Tetons National Park, and, I tell you what, I'm not the kind of person who's impressed by mountains and lakes and such--and I haven't been since I was about 6--but everytime the lake just outside Jackson Hole kicks my ass in the very best of ways. Food for thought. Appx. same as Estes Park, just slightly cheaper and a bit further away.
Probably comes out to about 800$ in structural costs.

C) Minneapolis --> Cabin.
I don't think I need to sell you on MPLS, it's the best. The problem with this plan, in all honesty, is that the cabins in Minnesota aren't near anything interesting. They all seem to be an hour outside of Duluth, which = exactly nowhere. So... yeah. If you're confident in our ability to make ourselves interesting, then MPLS would work just fine. If you liked the idea of a Park in the day and a nice town at night, then this plan's not for you.
Probably comes out to between 700$ and 900$ in structural costs, which, again, doesn't include activities or food.

D) Chicago --> Buffalo/Toronto.
This plan takes advantage of the fact that we know people in these places. Chicago's got Michelle, who is cool and could show us all sorts of neat stuff (and hopefully let us stay with her) and Buffalo's got Lars. Well, Lars' in Rochester, which is an hour from Buffalo. And Buffalo's two hours from Toronto, which is supposed to be New York City but clean and nice. Oh, and there's Niagra falls up in there, too. This may turn out to be either slightly more expensive or slightly less expensive, depending on when and how we decide to fly to CHI and BUF.
Probably falls somewhere between 700$ and 1000$ in structural costs, depending on how many people and how much our friends love us.

E) MPLS --> Chicago.
Same advantages of Chicago trip, but into Minneapolis first. Flights probably only into MPLS then out of Chicago, so that's cheaper than plan d). Probably between 650$ and 750$ in structural costs, but that could go up or down depending on how we get to Chicago and where we stay in both places.

So, pick a letter in the comments or roll your own.