Way of the Open Fist
Alchemist and Witch preparations are available. Fortitude Tonic and Can of Whupaz are recommended from the Witch. Shops spawn normally. Two of the following three altars spawn: Binlor Ironshield, The Earthmother, and Taurog.
There are two ways to approach this challenge. First, you can play standard monk (go for Orc Monk), and use Spoons, Wisp Gems, , Skullpicker, and to raise your damage to crazy levels for a monk. With the right setup, you can easily take on Meat Man 5 levels above you. Certain shop items and glyphs are helpful with this. If you go this route, be sure to save your Fortitude Tonic for the middle of the boss fight.
Another slightly more unconventional strategy is to take a Gnome Monk and bypass the boss's Weakening blow ability with fireballs. This works well with an Earthmother strategy, since you can get a large late-game mana spike.
Do standard Monk regenfighting stuff as much as you can. Before you level up, clear out all the visible mana burn and poison plants in the way. Prey on high-level Gorgons, Vampires, and Meat Men. Wait to worship Earthmother until you're ready to fight the boss, as it becomes very difficult to move around when you can't clear away plants. For the boss, you can use a strategy to get a bunch of free corrosion damage on the boss, or you can use a strategy to fireball the boss down.
Platemail works well here, comboing with the Monk's natural damage reduction and if you're feeling saucy to massively reduce damage done. Unfortunately, it does leave you vulnerable to Nagas, who would normally serve fairly well as popcorn. Obviously, the monk loves damage items, and if you go Gnome, a Trisword and Whurrgarbl can translate into a bunch of extra damage on the boss. If you go the fireball boss kill route, standard caster items like Crystal Ball and Battlemage Ring are good finds. Viper Ward and Soul Orb give you a great deal of freedom to clear plants, and give a great deal of CP when you're done clearing plants.
While it is not an item, HALPMEH is very good here as well, allowing you to clear poison plants with impunity, as well as playing into the Monk's attrition strategy by offering more health/tile explored.