First job was to remove the existing track. It was laid in the garage in November 2010 when the temperature was well below zero, as a result when brought in the house the rails expanded, although the track didn't move the curves had a negative camber! When released the diameter of the oval expanded by about a quarter of an inch. I then had to plane off the no-more-nails type glue, as it hand't worked well, this time I stuck to track pins. Hint: Hornby pins are larger than PECO, but strong enough to go into plywood.
The job was made more complex because of the folding board, this means the track needs to be cut at the board joint and soldered to small brass screw heads to ensure secure alignment. Also every rail needs a wire to bridge the gap, laid above the board because of the double-skin board design.
Further complications are that Hornby and PECO have different geometry for their curved points (I was using various points bought cheap at shows or off ebay), and the size of the board didn't allow two standard straights between curve and board joint. This restricted point placement, and meant I couldn't use the power feed tracks - I just wired back to a terminal block connector for easy connection of controllers.
This shows the final layout, as you can see I had allowed for the extra tracks when I painted the board, and there was space for the outer platform and siding. I Think I got the maximum number of tracks on for maximum fun! All points are within reach of one side of the board too. With two controllers I can now play with my son!