(thanks for the heads up on Ft Worden)
what do you mean "ruined?" If it was operating OK before the defrosting, I'm betting that the amonia machine is still OK. Do you now have warped plastic interior? If so, can't you heat them up again and press flat with suitable pieces of plywood and allow to cool back to the original (or near original) shape?
If you really do need a new fridge, look for references to a vendor called "Palomino". Great fridge prices. Dometic has a series of fridges that are designed to fit in the vintage spaces, with maybe a 1/2" shim to make the cabinet fit tight.
Installing a new fridge generally requires adjustment of the height of the shelf immediately above the top of the fridge and maybe trimming the plastic vent enclosure.
In the photo below from my 31' Excella, the fridge is on the end of the line of cabinets, so if there was width problem you'd only have to move the end bulkhead. These bulkheads are easy to move, you just unscrew the metal channel from the wall (that does cause a problem with the top shelf, which may have to be lengthened--making it shorter isn't a big issue).
If you have to move the top shelf up or down, you'd have to make a new bulkhead on the left side of the fridge. I addressed this problem in my 27' Overlander (which has a fridge in the same spot) by making a left bulkhead that went up to the upper cabinets, then I could put in a new piece of upper shelf at any height that was only the width of the fridge.