Where are you getting that it’s a 7 to 10 day drive? Using the Rand McNally Online Mileage Calculator, I get that from JFK Airport in NY to Portland, Oregaon, it is:
So say, 3,000 miles; even if you keep the hammer at 50 because you’re towing a U-Haul and drive only from 6 am to 6 pm every day (that’s 10 hours of actual driving time and allowing 2 hours for pit stops, which is generous), so you only make 500 miles a day, that’s still only 6 days.
And you can speed things up by driving faster–55 is safe with a U-Haul, and if you’re not towing anything, you can make even better time, driving from 6 am to 8 pm every day, and having shorter pit stops. So that’s not 7 to 10 days. For you to take 10 days to get there, you’d have to be making only 300 miles a day, which is leisurely even by Grandpa’s standards, and I have to assume you’re planning on either sightseeing or visiting relatives along the way. Or else you have a compulsive outlet mall shopper in the car (“Oooh! There’s one at the next exit!”)
Anyway…
[attempts to visualize 100 pounds of meat as a big pile]
Hmm…that isn’t really that much meat. I’d get a bunch of styrofoam coolers (you probably don’t want to inve$t the money in those huge double-layer insulated molded-plastic soda coolers, because what do you do with them after your trip is over?, but the styrofoam ones you can always use), pack the meat it, add some dry ice, and then put them all together in the trunk of the car or the front of the U-haul, wrapped up snugly with a bunch of blankets for insulation, and then DO NOT OPEN THEM TO PEEK en route, until you’re ready to put them into their new freezer. Every time you open the lid to peek, you let warm air in, so the secret is to bundle them up and then leave them alone.
And actually, since you’re making this trip in the dead of winter, and you’ll be traveling across the northern tier of states, if you have the coolers in either the U-Haul or the trunk of the car, IMO they’d stay plenty cold enough that you wouldn’t need dry ice–just use regular ice dumped in on top. Big chunks of meat will stay frozen all by themselves, with just some ice, if they’re insulated and the ambient air temperature is fairly low.