Those are beautiful photos Highup.
I have plenty of space around here to store scrap metal. I don't think anyone is paying for that stuff right now. Economy is absolute crap in my area. I think what I would do is take any decent pieces down to the my workshop & store them in the outdoor covered area in case we can figure out how to use them for a project. I will likely not use the metal beam in the new shed as it doesn't look like it would fit, but I will keep it if it's in decent shape.
I'm thinking building a shed from scratch would be the best approach bc it's hard to find people who will actually install out here for less than $2k. If I do my measurements right & build stuff a piece at a time I can then remove the old shed and assemble the new one. I'm thinking of seeing if any of the roof parts from the metal shed can be reused though- at least as a temporary cover. So, I'm thinking I can frame each wall and label everything. I saw some sort of concrete blocks with notches in them for shed frames in a photo somewhere. I want to see if those are available & figure out the best lumber to use for the bottom plate. I want to avoid pouring more concrete if possible.
So, I'm thinking frame with studs 16" on center w/ horizontal pieces in between about halfway up for reinforcement and spacing, rafters at 16" on center as well (also with horizontals at halfway up) 2x6 or 2x8 ridge board & custom gusset plates notched for the ridge board (that will help avoid the need to toenail stuff), hurricane rated hangers (not sure what they are called exactly) for the rafters where they meet the wall on the outside so I don't have to toenail near the bird's mouth and risk splitting the wood. Small gable fan up top on back wall (above the wall and in the gable part), small window in the back wall centered under gable fan for some sunlight), solar powered lamp rated for outdoor use in case power is out & it's dark inside, etc.
If the sort of lean-to overhanging the front edge of the shed makes it too difficult to get a decent height, I might stagger the roof and have a lower portion underneath the lean-to and then have the rest of the roof with a steeper slope for my headroom (and maybe some storage for supplies). Front would have simple custom made double doors where one door overlaps the other. Expanding foam sprayed between studs, Reflectix on the ceiling.... I might even dig some French drains to help water drain a bit better.
Pic with simple double doors & the notched support blocks
Various sketches of ideas for the shed & rafter setup



Now some people were suggesting that I should have some sort of hatch to open the roof on one side to be able to access the well from above, but I'm not quite sure how to do that & still maintain structural integrity.