Nu-Wa 1995 Hitchhiker II 25RKSG - dinette table size?

My "standard" dinette table is 23" x 43".

Your 42" round table won't work unless you're tearing out the entire dinette, and even then, it will be really TIGHT. If you figure each chair requires an additional 24"; then you need a space approx 7'6" square.

If you're keeping the dinette seats, then with the leaf folded down, there's no place for knees on that side of the table.