I used a Terrain to create the floor itself, four layers (You can see part of it on the top edge of the picture, where it folds over visible, the net effect is simple molding and a step up) The texture maps are 2000x2000 (still has some jpg rough edges on the pattern) Then I used a series of different materials with occlusion maps (circle and zig-zag patterns created in photoshop- 3 different maps in all) to create the different zones of material. The cobblestone itself is a pretty decent image that was not created to be tiled, so I mirrored rather than repeat tile to help get rid of really bad seams (still has them, but not as noticeable.) Used both a bump map for depth and occlusion map (created in Crazy Bump) to create a different material for the mortar (thus the tinged color) as well as a specular map to help with the highlights.
I tried to create a full size terrain with all the cobblestone involved, but did not work as well as I had hoped. But your tips really helped otherwise for the rest.
I think the map for the zigzag may need to be bigger as there is noticable jaggedness. Which brings up a question: Should I use a different format than a max JPG?

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