I grow in a hideous, horrible cellar. Right now, with the rapid spring we are having, my basement is out of control with moisture coming up through the floor (dirt, with 1/2 inch of deteriorated mortar on top) and the walls (4 foot thick concrete; why? I don't know) are drooling with moisture. I can run a dehumidifier all day and all night and it will have no impact. Once things even out again in a few weeks, I'll be running two portable air conditioners down there. They pull a lot of moisture out of the air and they push hot, humid air down a 4 inch cleanout into the city sewer system. This works very well, but, of course, is not free.
Since you have identified a portion of the basement that you want to use, you should wall it off, so you can concentrate your climate control efforts on that part.