>>127160
Almost certainly doesn't need being said, but I recommend using Hammer++ if you weren't using that already. Have you ran through what the angles, timings, chokepoints and general scale of the map would look like and are satisfied with the result? It'll take far more effort and compromise to fix any issues with that once you've started working on the aesthetics and optimisation of the map (familiarising yourself with the basics of Source's occlusion culling system, func_detail, nodraw, lightmaps, etc. early on will save a lot of future work during the actual optimisation stage. The same goes for 3D skyboxes too, if you want to do one of those). You probably don't need to worry about these things too much for a not-super-high-concept first map. Decompiling various Valve maps and going through those in the editor to see how they handled things was very helpful during my learning process, they still made mistakes or did things sub-optimally even in their later maps (not "gamedesign"). Testing the map with a furriend and/or bots will be helpful, too.
>I was thinking of creating a new VMF file and making each room textured while compiling each step, and using this draft as a reference. Just not sure if that's a good/bad workflow?
Yes, save iterative copies of your map with a naming scheme that'll make sense to you when you eventually need it.