Block a user
Monitor power and shut down if voltage gets below limit in webform (software)
Moved hardware part of this question to W1CDN/vulpes_hardware#3.
Monitor power and shut down if voltage gets below limit in webform (hardware)
Figure out how to power this thing
Make a schematic for the ESP32/DS3231/transistor board
If existing wireless network, report IP address to user somehow other than serial connection
People are just going to want a screen, but using as an AP should be fine if you're in the field.