Quake1/2 mapping is essentially the same, .map is similar to HL's implementation with a few differences. A quick search yielded some results:
Q1 -
http://www.gamers.org/dEngine/quake/QDP/qmapspec.htmlQ2 -
http://www.gamers.org/dEngine/quake2/Q2DP/Q2DP_Map/Q2DP_Map.shtmlIm going to outline only Q2 now
There are quite a lot of tools for Q2 available though many are scattered around and hard to find
http://home.insightbb.com/~gryndehl/q2compile/quake2.html one of them with sources, i remember using tim's tools but not quite sure about the real name.
Entities are defined in .fgd's also hard to come by
Im not a big Q1 guy so i don't know the specifics of it. As far as textures go over the years i've never seen Q2 use .wad anywhere, textures are defined as .wal and dumped into folders (similar to source materials) either in .pak or in the folder named "textures" in the mod's dir.
.pak format is quite simple as outlined here:
http://quakewiki.org/wiki/.pakFolder structure is similar to hl's with baseq2 folder being what the valve folder is to hl. Every mod has its own folder with a gamex86.dll inside which is the mod's code, any .pak files are loaded from the mod's dir and added to the ones loaded already so overlapping can happen, files in folders have precedence i think.
Model's are in .md2 format with separate textures in .pcx ?
There is an outline of the format somewhere so parsers won't be hard to code. No bone structure in the format so everything is pretty simple.
Textures if i recall right have some sort of flags or maybe faces do, for example making a ladder you need to set a face to be "sticky", there is no ladder entity like in hl.
A lot of info about formats can be gathered from other editors such as QuArK, or the "*radiant" variants.