I've not see the Black Belt Gaming video he is referring to (there isn't a link there) but has anyone used the Miniatures Handbook to try to run their own solo play games?
Dungeons & Dragons Miniatures Handbook Random Dungeon Crawl Deck and Board Game RPG Ideas
This shows the entire Random Dungeon Deck section of the 2003 3.5 D&D Miniatures Handbook. I uploaded it to share ideas with you and Robert at Black Belt Gaming on youtube. He was combining the 4e Wrath of Ashardalon board game components with 5e RPG books to create a solo random dungeon delve. This shows other ideas like a random dungeon deck using the D&D minis stat cards, NPC ideas, Bosses, Lurkers, Wandering Monsters, Traps, Special Cards, Monster Habits for combat, Using Magic statues and Teleportation, Locks & Keys, and Campaigns. It’s good for players who want a quick challenging game when they don’t have time to play the full RPG rules, to test characters without worrying about losing them in an RPG campaign, or to play without a DM, and for DM’s to test creative ideas. I also show some of my D&D and Star wars Minis and Stat Card Examples with the RPG stats on the backs. I end the video with clips form my upcoming Star Wars Epic Duels game.
I've not even considered it before, but it sounds like it could be fun.
I wonder how hard it would be to add solo-play rules to the SRD and build a 3e solo-play system.