GM techniques – strategies to effectively run a temporary online game

Other questions have set out well where online gamers and some of the tools available for running virtual games (Roll20, Fantasy Grounds, etc.) can be found. Many of these tools are costly and take a long time to configure a custom homebrew game.

Occasionally, circumstances prevent us from gathering as we prefer. The COVID-19 pandemic 2020 is a good example. In these times, it is important to find ways to continue playing together, even if this is not done in a standard, non-permanent way.

In this question I'm interested in what DMs and their players use to temporarily turn their regular pen and paper into a system that works with a remote group. I'm not looking for specific software recommendations, although a good answer can include one. Instead, I'm mainly interested in the high-level strategy that is used to continue role-playing while I'm not in the same room together.

I am specifically interested in answers that address the following common problems with this type of conversion:

  1. Temporary – Suitable for short-term gaming without running an entire campaign
  2. Role playing – support for high quality communication with little delay
  3. Content – handling of custom content, including maps, handouts, elements, etc.
  4. Combat – dealing with combat positions, distances, and surface effects that are typically performed on a combat mat