I think all source maps can be edit

Can someone empty the big main canyon and leave just the surface and all the roads, skybox, water?? I tried to empty what's inside the canyon, but I reached the selection limit in Hammer. 😐
Or does anyone know a good method to empty the main canyon only?? (I want to completely delete the main town from the map, but leave all roads there.) Basically, I want to replace the main town with my own small map only for myself.

Use BSP2Source and edit the vmf in hammer, if you don't understand what i just said you're better off just playing the map normally.

@Medic Gaming Are you answering to me? Anyway, I used "bspsrc_1.3.24" to extract the map, then "VIDE_0_45b" to extract the used content from the bsp file. The map looked simple when I first played it, but then when I tried to empty the canyon, it turned out it have quite a lot of things, which I need to delete maually, otherwise I exceed the selection limit in Hammer. So what? I just wanted to completely remove the slightly elevated town from the canyon with leaving the connecting roads in place. So what?

SFM maps are ♥♥♥♥♥♥ up.