Thanks. My thought was, the cultural & musical intermixing of minstrel/black, German/Polish, & early Country/Western (I can never keep straight which were the "tumblin' tumbleweeds" & which were the "she done me wrong"

) lead to what we call rag, jazz, & blues. They wouldn't sound exactly the same, or be called exactly the same, but they'd be equivalent. I do wonder if R&R even develops; it seems to me, some specific threads have to come together for that. I also thought, ITTL, there'd be stronger Latin/Caribbean/calypso influence that might replace R&R, or beat it to the punch, in effect.
I haven't forgotten the effect on westward expansion. I'm also using stirling-powered airships, so it'd be
fast. And between airships & cars, I thought there'd be a) an
early "FBI", to deal with interstate escapes/crimes leading to b) much more frontier law & order (more like Canada than the U.S.) & c) no Indian Wars.
I have some doubts about introducing railways. As it stands, railways develop a bit late, because highways & airports dominate from 1830 or so, & only into the 1930s TTL do railways begin to take long-distance freight/travel away from highways, as cheaper, more efficient, &/or faster, as trains get
fast (125mph+). (By the 1970s TTL, they're maglevs doing near Mach 1.)
Oh, and the CW: given machinery, I'd expect it not to happen at all...which leads to the survival of slavery in law, but more/less not in practise, except in isolated circumstances. Slavecatching still survives into the 1910s, but it's rare, & demand is low.