Jim,
It was an incredible trip. You need to do one when you can. I agree with Tom & Ray that you can't possibly take enough parts and tools to always have what you might need. I replaced belts and hoses, all hydraulics plus front brake pads and rotors before I left. I took a distributor cap and rotor, a 3/8" drive socket set, some combination wrenches, a couple pair of pliers, and a couple of screwdrivers. It turned out I had too many tools and not enough parts. But contrary to Tom & Ray's observation, parts availability seems to be better than it was 30 years ago, certainly for the older cars like that TR3 and my MGA and my TR6. Moss doesn't have many parts for the TR8, but there are plenty of other good sources.
The most important thing to have is some flexibility in your schedule. We made it back for my Dad's 95th birthday in spite of the water pump failure, but only because we had some extra days in our schedule for sight-seeing that we didn't get to do. We were also fortunate to have family 40 miles from where the pump failed, so we had a place to stay. Try to plan your breakdowns around family visits! And with the TR8, we were able to disregard Tom & Ray's advice on maximum speed, cruising across South Dakota, Wyoming, and Idaho at 80 mph (sometimes a little more.) Three other essentials for travel in a classic are a cell phone, of course, plus AAA with maximum towing range, and a VISA with a large credit limit!
Ken Morton
Anchorage, Alaska
1980 TR8, 1973 TR6, 1965 Volvo PV544, 1958 MGA, Jeep Cherokees