To Have or Have Not (Anymore)?

In preparation for summer-long touring, in a few years, we're considering replacing our 1977 Argosy 28 (rear bath, twin bed configuration) with something larger and with more storage. We're also considering modifications to the Argosy (e.g., replacing the jack-knife couch with a dinette, replacing the book-case and fold-down table with cabinets). I'd appreciate opinions on whether the long-term value would be higher in original (good) condition or with tastefully done modifications. It is unlikely we can match the interior material but the wood would be stained to match.



Also, I've reviewed posts on values and I'll do some research, but if someone has opinions on this I'd appreciate that feedback as well. Thanks all.