Here's a look at how I finished up the base for the tomb...
Before working on the base, I tackled the transition to the rear of the rooftop graveyard. I used one of the Sigmarite Mausoleum/ Garden of Morr wall sections to frame the short stairwell. The wall was raised up on a row of foam stones and I extended it with some carved stones made from Aves Apoxie Sculpt. Since I was running low on parts to cannibalize, I used some square plastic rod to build the tall post on the left, and carved the point on the right out of styrene plastic rod.
The short walls on either side of the steps were made from insulation foam, topped with thick PVC card, and I used the rounded tops of the mausoleum gate to make the railings. I also added a bit of broken fence on the corner.
The broken wall was pieced together with stonework cut from a mausoleum base, glued onto PVC card which increased the thickness and allowed me to carve corresponding stones on the opposite side. I even added a row of skulls near the top and added some spikes to match the mausoleum wall.
At this point, I decided NOT to mount the entire piece on an MDF base. The whole tomb was already large enough, and a full base would have added an extra inch all the way around. Plus, I liked the idea of the front steps forming the edge of the scenery and resting directly on the tabletop. Having an extra boundary of sand and grass wouldn't add anything to the piece. So, I filled in the remaining gaps in the stairs with skulls and called it a day.
I still needed some MDF basing, however, as the rear mausoleums needed to rest on something. In order to have the MDF board under the rear half sit flush with the bottom of the foam and the steps, I needed to slice off a layer of foam and then attach the MDF board. I cut a piece that was L-shaped so it would provide basing under the mausoleums and the rubble along the collapsed side.
I traced out the shape of the base, and then cut it out on a scroll saw.
I beveled the edge under the rubble and marked out the placement of flagstones around the mausoleums. Then, I cut out some of the spaces to create an irregular, stepped surface that would look as though the flagstones were falling into disrepair around the edges, similar to the base that I had made for my watchtower.
To reduce the overall width of the piece, I removed the sloped hill along the right side, and I replaced it with more stonework. I used parts of the mausoleum bases to fill in the missing sections. Since there wouldn't be a solid, MDF base underneath the wall, the plastic provided more support to keep the foam edge from chipping.
I attached the MDF base with a mix of construction adhesive and hot glue. Then, I used wood glue to apply sand and gravel over the foam rubble pile. I also included some foam stones to represent the broken bits of wall. Like all the other foam, these bits were coated with Mod Podge and black paint to protect them.
I spray-primed the insides of the mausoleums black, and then glued black styrene card behind them so no foam wound be visible through their gates. I also painted the base black where their floors would be, so the only thing visible inside would be a dark void.
The mausoleums were then glued in place, and I began applying the flagstone basing.
Each flagstone was individually cut from styrene card of varying thicknesses. I distressed the edges, super glued them in place, and sprinkled some sand and ballast in the gaps between the stones.
Only the top graveyard section and crumbling rubble remains!