Thanks for all the kind words everyone! Since folks were asking for construction pics, here are some random ones.
Stacking up rough cut foam to check the line of sight with some figures laying around.

Plaster rocks attached with construction adhesive and gaps and slopes covered with drywall. Figure I would coat it the whole board in it, but in retrospect that wasn't necessary for the flat parts.

First coat of water/glue/paint/sand for the dirt. Used cheap house paint samples. This was followed by two additional drybrushes of lighter browns also using cheap house paint.

First layer of flock, using the method in the video below. I was kinda skeptical of the scenic cement nonsense but it worked pretty well.

+1. Fantastic looking terrain board. How did you do the grass effect?
I used the power of.... The Clinic.
Charmingly dated video that basically runs down the Woodland Scenics method of making model railroad terrain, but it would work with any flock you can find. The stuff about benchwork and underlayment isn't too useful for wargame boards as their method is both heavy and prone to cracking when moved. But all the terrain work I did is lifted right from here.
Where I deviated:
- Underlayment is foam sheets.
- Rocks are drybrushed, as I wanted to add things like resin dry stack rock walls to match the same color. Their rock color system works on soaking into white plaster and wouldn't work on resin castings.
- Hit the final product with polycrylic varnish and water in a spray bottle.
That's a very nice result

The ground work is particulary good

Will you be doing more that fit with this or is it a one off?
cheers
James
This is a prototype for the construction method. I'm debating opening a game store in 6-12 months and I was testing out making really nice boards as a feature to draw people in. I'd also sell the finished ones after they were in the store a bit and make new ones to help with the rent and also keep fresh boards. The material cost is around $150 for a 6'x4' board, which is about the wholesale price of the typical plastic GW board I see in most stores.
My next specific project is going to be a 6'x4' commission for a friend. He wants a desert board to demo a Rogue Trader game in october. The size of the board leads me into my topic:
What I really want to spark is a discussion about elevation/topography on single piece boards. I think there is a lot of good info out there for modular tiles. If someone asked advice about modular terrain we could all rattle off the tile shapes you would want to make: plain flat, corner hill, side hill, straight road, corner road, T shaped road, straight river, corner river, etc etc. For single piece boards there is less out there. As I sat down to sketch out my friend's board, I found that I was mimicking modular board shapes: the one with hills on the corners, the ones with two roughly equal sized hills on each long side.
So I really sat down and racked my brain and came up with this:
White area is the "base level" of the board. Dark red is the "top level" of the board, probably 3 inches high. Light red areas are sloped between high and low. Black lines with hashes are exposed rock faces. White line is a road. Blue lines are dry riverbed.
Anyone have any other examples of boards with lots of different elevations and topography?