(1)increase kitchen working space,
(2)using vertical space (like above the rear dinnette/double bed area) more efficiently,
(3) smaller fresh/gray water tanks (I really don't need 15 gallons worth), Oh yeah, my gray water drain has ripped off the main tank so now there is just a gaping hole on the gray tank
(4) reupholstering (no plaid please),
(5) sturdier dinnette table,
(6) locking door knobs so I don't need to bungee them closed during travel (or find all contents on floor),
(7) probably need some floor patch work in weathering areas
(8) Increase bottom clearance
(9) ? change 1 7/8th hitch to 2 inch
Given your "never use the front for sleeping" style - the usual mod is to convert the front bunks into a perminant 2 person dinette. Leaving the rear as a perminant bed. No converting things back and forth then...
For your items above:
1) Many folks have added fold-up 'wings' on the sides of the kitchen to give more space. I pulled my stove and made covers for the hole and the sink. A nicer solution would be a fold-up cover that turned the whole kitchen into counter space, but that folded back IF you wanted to use the sink/stove.
2) I always wished I had one of the overhead storage bins in the Boler
we had. In addition to BEING storage - they made it easy to add a couple shelves between itself and the closet or kitchen OH bin.
3) I don't have any experience dealing with water systems. Don't really need them where we go so I just pulled it to make more storage. I'd think that unless you really needed the space - leaving them intact (with repairs) and just not filling all the way would be the path of least resistance.
4) Lots of folks have recovered their cushions. It's just a matter of how patient you are vs how detailed you want them to look. Squared with piping in the corners is the most elaborate - we just made new covers that were like form fitting pillow cases with velcro for the closure.
5) Sturdier than the usual "sawdust glued together with a picture of wood on the top"???
In the Boler
we had, I bought used a piece of 3/4" plywood (sanded, the cabinet grade stuff is REALLY pretty). The old table was used for the pattern and all the old hardware recycled by moving it over onto the new one. Well... I didn't use the post. I rigged a fold-down table leg out of some of the left-over plywood for that - but the trim and wall-mount were recycled. Looked a lot nicer than the original too.
6) Locking cabinet doors. I didn't have a nice solution for this one either. In the Boler
- I swapped in locking knobs (using the stock catches). In the PlayPac, no locking knobs - but I used spring loaded hinges. That worked for the small doors, but I added a couple hooks amd eye screws to the big doors. Not elegant, but effective.
7) floor patch... not sure if you mean floor covreings or the floor itself. New linoleum isn't hard. Many folks have used pergo-type floors - very pretty. Soft spots IMHO are best handled by thinking like a dentist: Grind out only what is bad and fill.
8) Increasing clearance - You're looking at raising or swapping out the axle
. That's the first thing on your list I'd go to a pro for. I personally liked the really low clearance myself. Made it fit my garage and didnt need a step stool to get in when camped.
9) swiapping in a 2" hitch - Pro job IMHO (I don't weld), but why???