After 6+ hours of coding and testing, as well as refining the wall tileset, I’ve finally completed the wall algorithm. Now it will automatically select the right wall tile (L-shoulder, cross, T-junction, etc) according to its neighbors. Below is a simple random wall generator that showcases the algorithm.

This is the first step to creating a powerful rogue-like room generator. I have the ground and wall tiles randomized now, next would be ground tile transitions. After that would be furniture placement (windows, chairs, tables, etc).