So I did wind up making a guide for getting the Playdate SDK working on a Chromebook via Linux. The major caveat is that you cannot use a Playdate as a controller for the simulator, but everything else seems to work, at least at first glance. I've been able to compile .pdx files without issue.
Maybe someone out there will be able to take it further than I have, but I'm happy to have gotten it working at all!
Here is the guide, if anyone finds it interesting or useful!