I set up a floor layout with Gargraves/Ross track but it was on a MDF/ Plywood base. My reasoning behind the decision was to pre make the layout at work and set it up on Christmas Eve. Since the layout was the perimeter of living rm it was a fair amount of work but worked out well.
I had a dowel at each joint in the plywood. The track then spanned the plywood joint. A screw on each side of the joint in the track ties held the joint together. I did not use flex track at joints. Tracks screwed down minimally, generally 2 screws per pc.
I did the same thing for a standard gauge layout, but used knock down furniture couplers at each joint.
Link to that post