The show takes place in the local high school, so it's not a huge layout.
There are generally two main halls on the ground floor, with the connecting area also hosting traders. Upstairs is the flea market and another large room with some traders. I think the painting competion is usually upstairs as well.
The games are spread through all the areas and there are generally a large number of periods covered.
If you're coming by car, get there 20 or 30 minutes early, as there's not much parking at the school. There is overflow parking in the local business park, but that's the best part of a 10 minute walk away. There are bus stops either end of the road, and it's probably about a 4 minute walk from either of them.
My brother-in-law and I generally call it quits about lunchtime. However, that's because we're spent out, not because we've seen everything. I usually just glance at the games being laid on, despite meaning to spend more time looking at them. You should easily be able to keep yourself entertained until mid/late afternoon.
There is a food area (in one of the big halls). I've never bought anything from it, so can't comment on the quality. Falkirk is only a few minutes by car and has plenty of shops (although it also has a nasty one way system)
Hope that helps. Any other questions, feel free to ask