I live in a story and half log home with a walk out basement under it. I have my quilting machine in the basement and my sewing room on the second story of the house. I like it that way because I like the additional exercise it adds to my day.
However, I am claustrophobic and I can do okay in my basement. During the winter when hubby is in or while I am canning I move a portable machine down there if I am not quilting and sew just fine. I do have the added advantage of being married to an electrician. Lighting is never a problem.
My basement is dry and I never have a problem with mustiness. We do have a dehumidifier that runs in the summer. My basement floors are graded toward the drains (like all of them SHOULD be). We just leveled the frame for the machine on the floor where it stands. Mine is actually on rollers and stored against the wall but I pull it out to the same place always.
You really can make it work just fine. I am upstairs because I have room right now but I could easily work in the basement and do at times. Good luck with your new space!