I'm thinking of a folding baseboard 8'x3' with the joint at 4'. It will be 9mm ply and constructed just like an inverted wallpaper paste board with hinges the same and closing to protect the track. It will be on trestles. Thinking of a couple of flat steel bars bolted under the join to stop it sagging or a third trestle
At the moment scenery is not essential as the layout is envisaged to be an end to end shunting yard not necessarily with a loop which MG said is difficult at 3' wide. The idea is to see if 00 is for me or change to N later.
I know I'll have to wire the track across the join but I will leave the electrics until I've decided on the layout by trial and error.
Really at the moment I'm wanting views on the board I'm thinking about then I'll go and buy the wood.
I hope that was clear to understand, all in my head at the moment.

Rob