Hello
@HMiller,
My first thought for an answer to your questions was "Well, how long is a piece of rope?"
There are a lot of variables that affect the real answer, the biggest being what model of mill.
But after thinking about my own experiences, perhaps I can provide a little help....
Here's some shots of the old Cincinnati that I got:
https://www.hobby-machinist.com/gallery/albums/my-1916-cincinnati-3s-milling-machine.364/
I first saw it out in the snow with the base buried; the barn had been partially dismantled to remove a huge press.
I got mine delivered by a guy with a big boom truck, he was there picking up a huge radial drill that he bought and since my house was on his way home I gave him some cash to get mine too. I had him drop it on top of a thick plywood sheet right in front of my garage. I had raked up the gravel to put the top of the plywood flush with the concrete floor. I used some black pipe between the plywood and the machine. Then I could pull it in with a come-along. I even spun it around (once inside and I had the pipes out) by wrapping the strap around the base of the machine; as I pulled it unwrapped exactly into place. I have moved it a couple times since.
When I got mine I contacted Cincinnati Machine Tool thru a link on their website.
I had the model number "3S", but they could provide no info until I gave a serial number that they told me where to find.
Once I had that they told me the age (1916!), mass (11,000lbs!), recommended oil, etc.
A few things to consider:
1) How is the floor in your shed?
My mill is about the same weight as two pickup trucks....which my garage floor should also handle, but it is concentrated into a roughly 4' x 5' square. I make sure to keep mine away from some anchors drilled thru the slab.
2) There are a number of Cincinnati manuals available on this very site, even some that I bought, scanned and uploaded when I was trying to find my manuals. However, I believe you need to be a "donating member" to have download privileges (to help defray server costs).
See here:
https://www.hobby-machinist.com/resources/categories/cincinnati-except-grinders.30/
There are also some manuals on VintageMachinery here:
http://vintagemachinery.org/mfgindex/detail.aspx?id=2097&tab=3
Get a copy of the book "A Treatise on Milling and Milling Machines" while you're there. Great book!
3) for positioning:
-you may need more space around it to do any cleaning and repairs before you put it to work
-I have the vertical head for mine, but to use that I need the overarm pushed way back (like the "early peek" photo in my gallery album above)
for a few years I had it "backed into a corner" and that allowed enough space to get around it and push the over-arm way back.
(although I suppose that yours are the "new-fangled" dovetail style overarm, so maybe this doesn't apply)
-to add/remove the vertical head I need to be able to get the engine hoist manoeuvred around the front of the mill, you may need the same for a rotary table, indexing head, or even a big mill vise or large work-piece.
Have fun and be safe!
-brino