I traveled to Bangkorai from the Reach and suddenly realized that I missed one quest of Markarth's Aftermath. I decided I wanted to go back with the carriage my quest marker was pointing at.
However, I wasn't able to activate the carriage at all, even when my quest marker directly pointed at it. I recall having this issue with this carriage previously, but it seems that effort had been made to make it functional like it was meant to be.
I personally enjoy using traditional ways of transport instead of wayshrines, and I'd really enjoy having a fully interconnected Tamriel in the future ahead, even with Gates of Oblivion.