Bit of a layout from Dave for you all...
Great War games don't usually have too many roads to help with map scale, so most layouts start with villages (or what's left of them) hills or redoubts, anything that can help with the placement of scenery relative to how is was on the day, or as near to it as possible
CD allows for a maximum of x1 communication trench per module
The heights = to 50-75 yards in actual elevation
Layouts like this are not that common as usually both sides have a continuous front line; one like this would normally be a bit more scenario specific
Buildings can represent a small farm to a village or reasonably large town depending on how they are placed
The obligatory wire
x1 line of wire is fairly standard but it can be found up to x4 deep; which without armour usually makes for pretty hard work on any attacking infantry
Still, if you're defending you can never have enough :)
In set piece games gaps are usually cleared in the wire in front of the infantry jump off points
In CD, tanks breakdown on a D6 roll of 1 or 2 anytime they move off-road, which is reduced to just a 1 in games set in 1918, owing to the improved design of the beasties
Between our two sets (of trenches) me and Dave could easily do some of the largest battles of the Great War - well, the first couple of days of them anyway :)