I drew up a couple of quick sketches in Visio to get an idea of what materials would be needed.
Fortunately I already had a good supply of scrap insulation board, so all I needed was the MDF sheets, 1 x 2's, and some wood screws. Time for a trip to Home Depot!
I found pre-cut 2' x 4' pieces of MDF for about $7.00 each. However, when I checked the measurements in the store, I found they were actually slightly oversize. That's OK, I have a saw and I know how to use it. I still have all of my fingers too, mostly.
Screws were easy to find in the size I wanted, I needed 24 per board, so 96 total, and I'd probably lose a few, so better get a few extra. 13 bags of 8 screws at about $1 per bag.
Now for the 1" x 2"'s. I found some really crappy looking ones in the lumber aisle, but I wanted these to look better. In the trim aisle I found really good looking ones (select pine) for $4.50 each. I can get two (24") ends and one (46.5") side out of each 8" piece, so I needed 6 total.
I hauled everything home and got to work cutting. Cutting MDF makes a real mess so I did it out in the garage. I cut about 3/8" off the ends of the MDF to make them truly 2' x 4'. Then I cut all of the 24" and 46.5" pieces of trim as well. I cleaned up the mess and took everything downstairs to the basement for assembly.
Jonathan wanted to help, so I let him drill some of the holes and drive some of the screws. I used wood glue on all the joints to make sure everything would be nice and solid. I used some clamps to hold the edge pieces to the MDF while I drilled and countersunk the screw holes. The whole project took about 2 hours to complete, and I took my time.
I let the glue dry for a couple of days and then started cutting foam to fit inside the cavities. I actually had enough scrap to fill each board with one large section of foam. I sprayed adhesive (3M Super 77) inside the cavity and on the bottom of the foam and pressed it into place with Jonathan's expert help. As I completed each board I set it on top of the previous one to help weigh it down. This phase took probably 30 minutes to complete. I set a piece of scrap foam on top of the pile and put a couple of heavy boxes on it and left them to dry.
The next step is to start carving the foam and adding terrain features. One of the hardest things to get use to on these boards is the wood forming the border. I keep having to remind myself that the trim gets covered up by the terrain, so it won't be seen when these are completed. The cool part is that terrain features can go below level, so you can have really nice water/canyon areas.
Since these boards are for Ogre primarily, they are going to be in a dry, dusty desert motif. I imagine that lobbing nuclear artillery shells all over the place did not leave much in the way of grass or trees.