I just recently purchased my first WWG set, Mini Chunk, and am in the process of putting together enough pieces to do all the encounters in Keep of the Shadowfell that don't have pre-made maps (basically all the dungeon rooms inside the Keep).

With that said, I've noticed that the walls in Mini Chunk seem to be different than the ones in the other sets. Mini Chunk walls are big and thick, and take up basically an entire tile width. In the pictures of the other sets, it seems like the walls are just slim card stock, and can be paper-clipped together.

I'm just curious why the walls are different for Mini Chunk? Will I still be able to use the modular Pro Masterboard (foam + velcro) trick for other sets? Are the floors always the same? I'm likely going to get the ExteriorWorks set and some others if I have success here, and I'm hoping I might be able to re-use some things between the various sets at times.

Castleworks also has the thick walls, for the castle walls, the buildings have thin walls. This type of walls allow figures to be put on top of the walls, or to have multiple levels of walls stacked up vertically.

I don't see why there would be an issue using them with other sets.

The modular master board, is that where little pieces of velcro and stuck to the bottom of the ground tiles? If so, that can be done with anything you feel like. All the newer set should have square tiles like that. Although there is some variation in tile size between the sets some are 6x6, others ground tiles are 7x7.