It seems like in this day, it would be easy to find some reliable information from a well-trafficed site like Facebook, Twitter, Yelp, Trip Advisor, etc.
The quality of info on slot car raceways on the sites you mention is poor at best; it certainly isn't very reliable. I know, because I use most of them as sources of info to populate Slotblog's Raceway List.
Please understand that most of the entries in the Raceway List come about because I see a mention of a raceway somewhere and start hunting down the info needed (though MG Brown has been a big help with the list!). I've been known to call raceways seeking the info for their entries. I used to request pics of their tracks when I couldn't snag them from their website or Facebook page, but almost never bother to do so any more, as fewer than 1 in 10 will actually follow through on pics, even though they'll tell me on the phone they will get them to me.
As I posted years ago, the "industry" doesn't seem to have any interest in an accurate and current raceway list, the raceway owners themselves, as a group, seemingly don't feel it is important, and only a very few racers ever contact me with updated raceway info.
As best I can tell, Chris, you and I are just about the only guys who feel the need...