Remove Factory Dinette For a Few Years Then Put It Back?

If you do mess it up taking it out, it shouldn't be too hard to construct something equivalent if you're reasonably handy. A wood framed box isn't exactly rocket science to build. At least on my dinette, there aren't even any angles other than right angles.

Make sure that you don't have anything hiding under the benches that can't be moved, like batteries or LP tanks or outside storage compartments—or, if you do happen to have them, that you're taking them into account when you design your desk setup.