Hi ksterling, welcome to the party!
I'm still a newbie myself, so there's a lot I don't know about your question--but, if you don't already know this--the Kindle can read .prc files without any conversion. There are many wonderful books right here on MR. Click the "e-books" link on the home page and pick "Mobipocket" format. Last I looked, you have about 1900+ choices of books that have been uploaded by the good people here. I'm about 2/3 of the way thru Great Expectations (
https://www.mobileread.com/forums/showthread.php?t=16211). I highly recommend it!
Regards,
R.L.