Danno,
I'm a little confused by your post... but I'll throw this out there anyway.
I'm planning on starting my own Great Loop cruise next year, and will be single-handing most of the way. The big limiting factor for any sailboat is going to be the bridges in the Chicago area, which do NOT open and have a maximum clearance of about 21'. There's no way to avoid or go around them.
For this reason, I chose a smaller sailboat, with a deck-stepped mast. I think this will allow me to drop the mast more easily (and cheaply) when I get to Chicago, and raise it again when I get past the low bridges... or maybe not until Kentucky Lake.
Also, if you were considering the Trent-Severn waterway or Rideau Canal routes, you'll have to drop the mast for those too-- Max clearance on those is 21', if I recall correctly.
Otherwise, I'll just repeat the advice I've seen in most books: Most people don't get to cruise on the boat they want-- so they go with the boat they have. If you have a 45cc and it meets your basic cruising needs, you'll find a way to make it work for you.
Have fun planning the cruise!
--Jon