Lets see now: Driving across the USA I would want a car bred for the Autobahn and tested on the Nurenburg Ring. But no low slung sporter with stiff suspension as they are too hard to get up out of or ride for long stretches with old legs stretched out like that - guess I would prefer a Mercedes AMG 12 cylinder sedan.
Best gun choice, since I see little point in spending $100,000 to get something designed to be understated I think a Filli Rizzini sidelock with bulino engraved vignettes covered with scroll on the rest of the metal plus the most extreme wood finished to show that wood (not some reddish brown varnish) to best advantage would suit my tastes. Actions the same as the English guns and finished every bit as well. But I could be sidetracked by a Lindner Daly Diamond Regent Grade in 20gauge however they are outside today's question.
Rifles are another story. Double rifles are nice but I see no point to a rifle if it isn't a one holer as in all bullets in the same hole. An American made bolt on the Mauser pattern as executed from scratch by Rudy Wells (late from Prescott, AZ) would satisfy my requirements for the Best.

Footnote:
All checkering to be done by Americans.