Todd,
Yup, thumbing off the portal is fairly easy, although my experience has always been that it's the little old lady in the banged up toyota corolla, rather than the fat guy in the shiny, EMPTY truck, that will stop and pick you up. I've done it a bunch of times and never walked much further than that first bend in the road, before getting a ride.
It's also a good idea to just hang out a while at the store and chat up the folks to see if you can get a ride.
IF you're not in a hurry, it's also a good idea to call ahead to the Dow Villa and get one of the cheap rooms ($55-60) and get in that hot tub. nice way to end a great trip.
it's also not too bad thumbing on 395.
bob