I'm very excited to read your message. I'm Frank Ropp's grandson. I'd love to have a copy of those letters you mentioned from WWII (and share any other info). I have copies of his service records, etc. but nothing personal like letters. That info has been lost in our branch of the family tree. I'm also glad to hear that he was a kind and smart person. I didn't get to know him until his later years when he wasn't doing so well. Also, I can certainly get you in touch again with my dad (Frank Jr) and my uncle Steve (both on Facebook).
Looking forward to hearing from you!