... carport?
The roof will need to be braced up and footing redone too, as I believe it has no wire, rebar, etc.
Basically a job my grandpa and neighbor did many years ago, and it is badly cracked.
Also, although I always wanted an enclosed garage, the carport is a little tight, so would it be best to plan on converting it into a great room or similar?
The gun safe/safe room got me to thinking about this, as this would be about the only option I have to add a safe room as the rest of the house is a crawlspace.

Oh, does any of this kind of work add value to your property?

Commercial prices for concrete demo and haul away runs $1.75-$2.75 a square foot.
Note this is in my area; your prices may vary.
Bracing the roof - the cost of timbers, wood framing, ties if needed.

Pouring a new footing - one footing do it yourself - mixer rental, bags of concrete, aggregate, finishing tools
Re-pour the slab $3.50-$5.00 a square foot

the above numbers are plug in numbers used in my area for estimating - your number may vary.  usually not much difference between commercial and residential for flat work.

As far as value goes, maintaining the slab and structure/foundation will not add to the value of your home.
Enclosing the carport and making it into actual usable space with heating/air, electric, lights, insulation etc. will add value to your home.
Consult a real estate agent to determine what this will add.  So you do not go overboard spending on the work.
Note if you choose to enclose the carport do not forget the footing for the new walls.

Just weighing options here.
Would it be better leave most of the old slab in, and build a crawlspace over it?
Would still love a garage, but think a detached one would be my best bet.