Hello AM from up the road in Inver Grove Heights.
Is this perhaps the mill up at Mora, MN? There is one on Craigs List similar to what you are describing.
I am thinking it is an Enco 105-1132. This model still shows up on the Enco website, but is listed as discontinued.
Looks like it used to sell new for $1400, but its hard to tell when that price was valid.
Looks very similar to a Grizzly G1006 mill - may even be made by the same company. Grizz still sells theirs for $1475 (shipping included).
http://www.grizzly.com/products/2-HP-Mill-Drill/G1006 The website says the G1006 weighs 680 lbs (shipping weight). You can separate the mill from the floor stand for easier handling. It may not be too difficult to remove the milling head from the column to make for smaller, lighter pieces. You can download a copy of the operators manual on the above site. It might give you some more ideas of what to look at on the machine.
The one I see on Craigs List appears to mounted on an Enco stand with a chip tray (also worth something). Looks like it has a fair amount of surface rust in the photos - not too difficult to deal with, but you would have to clean it up. I would ask to see it run and listen for any bearing issues.
As far as price: I don't know. That's about 1/3 the cost of a similar new mill, and it says "OBO." I guess perhaps $500 if it comes with the stand, some tooling and a vice better than that shown on the photo.
As far as the round column discussion goes, I have never owned one. There are lots of round column owners on the forum. Also lots of "former round column owners."
Some will say that the round column is a disadvantage if you need to elevate the head often to change tooling (you then have to indicate back in on the work piece). Others say it is not an issue. Do a search for "round column mill drill" on the forum search bar, and you will find lots of opinions on round columns versus dovetail columns. I guess it comes down to what type of work you expect to be doing. If you plan to do a lot of smaller work, it may be a good candidate.
Perhaps one or two of the round column owners will jump in and give some advice.
Terry S.