Thanks so much for the helpful advice, Keith! I'll tinker with some of this ahead of (and during) next session and see if it helps. keithcurtis said: Those maps are very, very large. Wizards of the Coast (and other publishers) don't design their adventures with Virtual Tabletops in mind, unfortunately, and Roll20 attempts to adapt them as efficiently as possible. There are still some things you can do to combat lag. Some of them are in the Game Settings handout in the module. 1) Ensure that NPC tokens are not emitting light, nor have vision. Above all, don't give them sight. If you need to make sweeping changes, some can be made on the game settings page, or you can use more fine control on a page-by-page basis with a script like Token Mod. 2) The module defaults to Advanced Fog of War off . Don't change this. The maps are enormous. 3) Turn on "Only update on Drop" in Dynamic Lighting. 4) Do not add animations or music, if you can help it. 5) Police the PC sheets. Ensure that spell casters are not adding dozens of spells to their sheets. Other more general advice can be found here .