I thought it was interesting that on Pern they basically reinvented/continued classical music, but with the guitar as the basis of the string quartet rather than bowed instruments. They reorchestrated everything to work with the instruments they had. Also, their choral standards seem quite high.

I agree, you'd see a lot of percussion instruments (oddly, Pern doesn't seem to have as many--maybe a blind spot on the author's part) and a lot of vocal performance. With the lack of trained singers, you'd probably get more people with "regular" voices singing because of need, and less of a conviction that only "real" singers should perform (I think this is one of our current culture's nagging problems). Small, portable instruments, like guitars, zithers, harmonicas, violins, clavicords, would all do well onboard ship, and with proper care and a fair amount of kludging for parts, would last a long time. If catgut or steel strings weren't available, I would think people would figure some sort of string material, even if the sound quality changed. As time went on, people would compose for that string quality in mind.