If I could get A/C in my Datsun 1200 as well as some more comfortable seats I'd love to do it in the Datsun, but I know it probably would have problems in some areas like deep snow, etc. I've already traveled across the US a few times in my 1200's and it was always a blast whether by myself or with a family member. The only time it wasn't a blast was when I went through 1 transmission and 3 starters going from Seattle to Ohio before finally the clutch disk exploded....I had a vibration at high speeds (85mph+) that I couldn't figure out, but it did at least figure itself out I guess.
Another time for some reason one of my pistons cracked and my gas tank developed a small leak driving from Ohio to Texas...still made it and drove it around for another month before I found the piston was in two pieces, so I replaced the piston and kept going

Once I get everything situated with the new SR and getting it painted I don't know if I'll actually drive it cross country again or not. Deer, rocks, and bugs on a freshly restored car are the main reasons.