Agency ID (the ID assigned by the agency that owns it)
Name (e.g., "Department of Game and Inland Fisheries Fredericksburg Boat Ramp Fredericksburg")
Address (sometimes a street address, sometimes an identifier like "Dragon Run Swamp" or "Chincoteague Bridge)
County/City GNIS ID
Managing Agency ID
I'm not in any position to say whether this is a model, but it seems like a good sign for its modernity that Virginia only started tracking its own real estate holdings a couple of years ago, which is to say that somebody thought through quite recently what this should look like. (It's a terrible sign for Virginia that it didn't know what real estate that it owned until a couple of years ago, but that's neither here nor there.)
I'm seeing that some states go beyond the list of what they own, and also list all real estate that they rent (e.g., Florida). That brings with it a set of requirements not faced by state owned real estate, such as specifying from whom the real estate is leased, for what price, for what duration, and square footage. I suggest that we stick with state owned real estate, and regard any inclusion of state occupied real estate as a bonus.
Some states also include the year that the facility was built (if the real estate includes physical infrastructure), the size of buildings in square feet, the condition of the physical infrastructure (e.g., poor, fair, good, excellent), monthly/annual utility costs, year of construction, year last overhauled, occupancy status, date acquired, acquisition method, and structure size broken down by usable square feet and utilized square feet.
Some states only provide aggregate data (e.g., Oregon), which I want to specifically call up as being insufficient.
These are the fields that seem to be common among state-owned real estate datasets, and that I think are a good framework for a minimum viable dataset:
agency (e.g., "Fish and Wildlife")
real estate name (e.g., "Springfield Nature Preserve Visitors' Center")
location identifier (e.g., address, coordinates, or general geographic descriptor)
land acreage, if applicable
use type (e.g., "state park")
There are fields that I'd like to require, but I don't think that we reasonably can. Square footage of buildings, year of construction of buildings, geodata for holdings, GNIS IDs for containing municipalities, and unique IDs for each holding would all be awfully helpful, but this data is still useful without that information.