May not be that difficult....
I had to replace all the fittings on my PEX tubing. ALL of the plumbing was accessible without removing cabinets etc. Plumbing under the sinks was accessible by removing shelving. (screws)
The shelves rest on wood strips attached to the walls. Remove the shelf not the wood strips.
Look for removable panels in the storage compartments and there was a panel above the propane tank compartment that accessed the plumbing running from side to side as well as the holding tanks. Hopefully yours will be as easy....
For just a few repairs, the "Sharkbite" fittings are ideal.
Sharkbite But can get expensive. I used the stainless steel crimp clamps and brass fittings from Home Depot. They also carry the PEX tubing and the sharkbite fittings. .