Road Rash 64 is a really underrated game. As you say, the environment is alive, and nearly every race has a lot of potential for wacky slapstick fun. The driving feels really nice and is rewarding to learn.
We also were lucky enough to have an incredible physics engine programmer, so we were running a way better motorcylce simulator than made any kind of sense -- led to huge arguments with our CEO because higher level motorcycles were much harder to ride initially because they were modeled after real performance figures. We fixed that eventually -- Don was right!
Completely agree that none of the games from the CRT era look right on modern TVs. There was a group at GaTech that did some really nice visual simulations of scanline artifacts, but they haven't seemed to generally make it into emulators.