First off, welcome to the forum! Looks like you got a nice one there! Glad to see another '64, yours & ours are very similar...we're just a bit longer.
I checked out your photos, you mention wanting to change out your gaucho/bed to a dinette/bed. We are in the middle of doing just that as I type...I'll post pictures on our website when we are done. Hope to finish up the woodwork this next week, then get the cushions made...we'll have an outing or two without the cushions though...oh well!
Your floor damage appears to be just in a small area (at least from what I can tell in your photos), it shouldn't be too tough to fix. It looks like a patch will be fine, no need to replace the whole back end...unless the other side you speak of is much worse....it's hard to tell.
Anyway, you'll find all kinds of folks here willing and able to help with your restoration along the way, whatever it entails...good luck!