The most common way to connect sections of a modular layout is to use clamps of some sort from underneath. Any small offset because of a difference in the height of the module frames can normally be compensated for by using a deep clamp. Because of the extended profile board on the front of the Hot Springs Junction module there was going to be a big difference in the height of this module vs any AsiaNrail modules that would be connecting to it.
As seen in this photo, the side connecting to the Ntrak module has an extension that will allow it to be bolted to the Ntrak module below the main deck of the Ntrak module.
The other end will then present a 2-1/4 inch high clamping surface to the AsiaNrail layout.
At this point, all of the cork road bed is in place and I'm almost ready to install the track.