Those old LaserJets are absolutely bulletproof. My parents are still using the one we bought with our very first 486 clone in the mid 90s. I had to mod it a little to swap the serial port for USB a decade or more ago, but it is still cranking along.
I usually used Ethernet-connected ones, but I'd think RS232 serial at a doable bit rate was viable for most purposes.
Both HP-PCL and PostScript (I wrote code to generate both) can be sufficiently compact. (And you had the trusty built-in fonts, plus sometimes additional fonts in cartridges/cards, so fonts didn't necessarily have to be sent with the print job.)
What could be a problem for connection via RS232 is large images, or an unfortunate setup that rasterizes the whole page off-printer at high dots-per-inch.
