We live even more Northwestern than you, and also thought the once every 3 yrs was a good idea. The long travel times and larger than believable prices on airfare, as well as adjusting to the time difference was why we thought 1 longer trip was better than more shorter trips. We just purchased a 100 pts resale, and thought that 100 pts would work for the amount of time we could reasonably get for travel to that far of a distance. Resale was the way to go for us, the smaller upfront cost, as well as the lower mnt fees, and then the ability to bank and borrow for a combined total of 300 pts. So that is an option to consider, because the minimum for direct thru
DVC: 450 pts can be a lot of vacation time (150 x 3) every 3 yrs to use as opposed to a smaller contract. The actual reason DVC looked so much better for us was because we are a family of 5 (DD16, DS15, DS10) and finding a room to fit 3 growing children was becoming difficult (and $$$$). Imagine fitting 2 adults 2 grown teens (both taller than Mom) and 1 lg. 9 yr old who is just shy of Mom's height (takes after Dad's 6' football player stature) in the PO riverside trundle room.
As for every 3 yrs:
we have the next 5 trips planned using pts from '05 -'15
8 day trip in Dec 2 BR @ OKW 2006 252 pts (90 '05 pts, 100 '06 pts, 62 '07 pts)
6 day trip in Dec 1BR @ OKW 2007 120 pts (38 '07 pts 82 '08 pts)
Trying to save $$ by using AP & DDE for 2 trips!
7 day trip in OCT 1 BR @ VWL(hopefully) 2009 214 pts (18 '08 pts 100 '09 96 '10 - just let the 4 pts drop or give away)
7-10 day trip for Spring Break Mar 2012 @ BWV or BCV (hopefully) (only 1 DS left @home) studio or 1 BR 200-300 pts
5-10 day trip Sept 2014 ( no kids, only 2 airfares!!!)
So I guess once the 2 older kids have moved on to college, we'll be implementing the once ever 2 1/2 - 3 yrs. I guess at first I want to cram more trips in w/ the kids while they're still here.
So to answer your question, nope I can't poke holes in your plan, Only poked holes in our own "once every 3 yrs" plan the pull to use those pts and to go, go, go to Disney was just too overpowering for us (me).
Good Luck with deciding what's best (or funnest

)for your own family!