Cheeze1,
For the TL 213, the face of the kitchen cabinetry parallel w/ the frig front define a pretty wide aisle (38 inches) that could be totally opened up from kitchen to cab! Currently the 38 inch wide dinette takes up 6 inches of this aisle, and the sofa seat encroaches by about 15”. This leaves only a 17 inch aisle now. You are right to hope for a possible 18” more open aisle from kitchen to cab, where the two seats are 26 in apart.
Very Approximate widths (inches):
32 for kitchen counter*
25 fridge*
38 aisle*
*add to inside wall to wall of 95 in.
6 outside storage
34 sofa upright, maybe 52 down
38 dinette
If you elevate and swap sofa w/ removed dinette (keep old water tank and little disturbance to pump and electricals under sofa) sofa is flush with kitchen.
On the 25” frig side, maybe remove the false wall of 6” outside storage for a reduced dinette that makes into a 25” narrow bed, or it could encroach on aisle a bit to yield a 30 in. narrow twin when made down. Here, still, you go from a 17” current aisle to 32.
I think you gotta forget the U dinette, as it sucks away the aisle you are shooting at gaining to get that ‘slide width’.
You will be losing outside storage.
Still, I am intrigued and will continue to ponder…