Masonite? typo maybe? I've never heard of Masonire......if it's different from Masonite, then I'm curious, having been a builder all my life.....I hate finding out about a product I could've used but never known about.
I do like to use Masonite for a lot of things, and it would work for this project, but I much prefer Formica from Home Depot. (or any brand of laminated counter top.) I like the looks of a wood edge for such, like shown in the picture of my bench below. It's put on with a contact adhesive, where, using a notched trowel, you spead it over both the top and the existing bench top.....let it dry to the touch and carefully place it together. Permanent on contact. I know that scares some people but it's really quite easy to do it.
I use a trick a countertop man showed me once, using old venetian blind members that are curved in cross-section. I place them front to back on the benchtop every 4 to 5 inches, to provide a "standoff" between dried adhesive on the bench top and the dried adhesive under the Formica top......lay the Formica on, place it where you want it, then start removing blinds one at a time and press down until all blind members are removed and then press the Formica down even harder everywhere using a rubber or plastic mallet and short 2x4 under it.....instant finished top.....no paint....lasts for longer than you'll live.
Then, once you have a new top you can get out your router and rout grooves for your track if that's really what you want. I don't bother with track, having found it plenty good and strong, and easier, just to use Inline Fabrication mounts.
As for your existing door with lamination problems, couldn't you just glue it back, sand, and just place the formica?
For bench edging I used Alder hardwood 3/4"x 1 1/2" facing stained and varnished. I like the idea of raising that a 1/16" or so above the bench to stop rolling bullets and cases from falling on the floor. But I'm old enough to find it a royal PIA to search the floor for and picking up dropped components. I do suggest a router to clean up formica edges using a flush bit.
That's a very old picture.....3 presses and a bench primer later I have much less room and thankfully discovered Inline Fab mounts to quick change what I'm using......and I use an old horizontal file cabinet to store the presses not being used.