You still have your domes. However beyond geosynchronous orbit lies a asteroid that is the counterweight.
You several option with this asteroid. You can opt to populate it with levels creating a mega dungeon that you climb UP to. A crazy dungeon in the spirit of Barrier Peaks or Anomalous Subsurface Environment. Or you can have it essentially hollow with a hollow world environment.
You can have more domes spaced along the beanstalk each with their own levels of gravity until you reach zero G at geosynchronous orbit. As for the counterweight asteroid note that the "deeper/higher" you go the heavier the gravity becomes. Something to add to the other craziness.
To me the Old School Renaissance is not about playing a particular set of rules in a particular way, the dungeon crawl. It is about going back to the roots of our hobby and seeing what we could do differently. What avenues were not explored because of the commercial and personal interests of the game designers of the time.