In addition to the fluids I see no one mentioned new rubber:
1 - I would NOT trust tires that are known to be more than 10 years old on a 2000 mile road trip unless you are taking all local roads at <40 mph. Even then I'd be a bit leery. Change those tires! Call ahead and make sure someone has them in stock. the originals were V rated, seems only the Z or H rated ones were available last time I needed tires.
2 -Round up a spare set of radiator hoses, the little funny pre-bent hoses for the intake/throttle body area, and heater hoses. It's been years, but I racall at least one of the hoses is one diameter on one end and a different diameter on the other, so you'll not get a generic hose to fit. You can buy a catch pan and antifreeze at the other end. inspect the hoses after the car has warmed up and driven a few miles to see if you want to change them before you head out, or if you want to take a chance doing the work on the shoulder of the interstate should one fail.
3 -Have spare serpentine belt, as already mentioned.
And of course pack the tools you'll need for the above belts and hoses.
And while I have driven newly purchased cars home on thousand mile road trips, they were at least known to be reliable local drivers. The several cars I've bought that sat for 7 to 24 years all left me on the side of the road a few times in the first several months of ownership. (read first 500 miles) so I don't know that I would recommend what you are planning. The last time I bought a car from long storage I went down to TX, got it running, drove it a few miles and realized discretion was the better part of valor and had it shipped. The good news was now that it was running it was cheaper to ship than a non running car.