first off, i know... source is JUST around the corner, but i really dont wanna have to deal with my PC crashing a million times, so yea... im gonna make one last map with hl1

so i know with source there are those textures for the sizes and everything, but hl1 doesnt, so does anyone know a good size for doors / inside building walls and the like?

Most everything is 256x256 for walls, with exceptions like 128hx256w

As for doors, open up a .wad file like for caen or donner and check out the door sizes and stick with those.

Doors are usually 56 units wide, 112 units tall. Interior walls look good at 128 units tall, since this matches with most textures, and it looks just right in-game.