I removed the front hide a bed on our Seneca and replaced it with a Recpro 72" power recliner set, here is a link to my post on it.
https://www.jaycoowners.com/forums/f...tml#post850987
Removing the dinette would be pretty straight forward, just start removing components, the table is screwed to the wall and on our 2018.5 it looks like the seat bases are just bolted/screwed to the floor. You will have some screw holes in the wall to cover or fill in but thats about it. Before we got our Seneca I did the same thing on our Winnebago 26P, I unscrewed everything and bagged and labeled all the parts with pictures. Put it on a pallet and shrink wrapped it all up. When we sold it, the couple didn't like it not having a dinette and I told them in about an hour, the dinette could be back in and they wouldn't know it was ever moved.....and they bought it.