Just wanted to share my workflow here, since it might help others. Feel free to share yours too, so other newbies can have some direction on how to start.
- Blocking out: I use https://blender-addons.org/qblocker-addon/
- Detailing: https://gumroad.com/l/VthLyO and custom static meshes (that I manage with https://blendermarket.com/products/asset-management/)
- Texturing/Lighting: I just randomly slap materials to my surfaces, and then I use https://blendermarket.com/products/baketool to create a single texture out of my entire map. Then I use https://github.com/Naxela/The_Lightmapper to create the lightmap for it. Using GIMP, I blend the two textures and I get some pretty nice shadows.