Back in 1990, TSR released a pair of maps: one of the (western) Forgotten Realms, the other of Kara-Tur. They called them Trail Maps, and these were no simple poster-sized map; much like the name suggests, they unfolded like a road map to massive size. Put the two together and you got the whole of the realms some 72”+ wide. It was epic. I had them on my wall for quite some time.
One of the benefits of working at an architecture firm is access to a full-colour large-format roll scanner. I think you know where this is leading… both trail maps, scanned and merged, with a bit of added continent to the south, all ready for your campaigning pleasure: