i had built myself one last year with some rather thick chip board but it was far too heavy to move around and not particularly good for gaming on.
this time i have used 3mm hard board and a strengthening frame made from pine. it is nice and light weight ans a big improvement.
The parts (8*4 hard board, i asked B+Q to trim it to 6*4) some 1" dry wall screws and some L brackets
top view
bottom view
in my living room
set up for its first game
my next project is to paint it and my scenery, as well as try and finish some more of my bikes!