Highly recommend checking out the original BBC radioplays. I wanted to work in the now defunct Radiophonic Workshop so bad as a kid because of them and their LotR. HGttG is my favorite case study in adaptation cause there are like 5 different tellings of the story across 4 different media all primarily written by the same author and they all have their fun quirks and idiosyncrasies.
If you read, specifically the second book by Kaloophid, Some More of Gods Greatest Mistakes the main series starts to make a lot of sense.