l4d2 & gm_hellskitchen

I’m working on a remake of the Hell’s Kitchen level from the original Deus Ex. L4D2 has most of the models I need to give it the proper aesthetics, so I’m using the authoring tools to build it, but as far as I know unaltered L4D2 maps don’t work in Garry’s Mod. What do I need to do for this map to work in Gmod? Just recompile in HL2: Ep. 2 and mention L4D2 as a requirement? Or is there something more to it?

I’ll post a WIP when I have substantial progress. V.1 will include the outdoor area, the 'Ton hotel, and the Underworld Tavern. Eventually I’ll combine everything attached to that area into one map.

Do the map using Source SDK with HL2DM or HL2 or something, not Left 4 Dead 2 Authoring Tools.