A friend used to own an old 120' steel single screw. We only needed a second crew member to operate it, and that included taking it through the locks. Not difficult at all, but my friend is very experienced with big boats (he currently drives an 85' tug in Alaska). Here in the NW, you can get a big boat virtually anywhere you can drive a small one. Lots of wide-open deep places!
Personally, my dream boat is a 120' Delta. I'll never have the money, but dreams are cheap.
Dick