one question:
1) does a 700 x 30-32c cyclocross wheel/tire fir into the rear chainstays? And is there enough room on it for a mud to accumulate?
You'll need to have cantilever mounts brazed onto the rear triangle of the frame. A local bike builder can do this for you. I've spent $30 for this to be done in the past.
Then....you can do all the fun stuff like picking out parts, handlebars, etc.
Also you'll need a cyclocross fork.
Take a look at the bikes in the "post your cyclocross bike" thread to get some ideas on what people are using.
other than canti brakes, cross fork and cyclocross tires the rest is mostly road bike stuff.
jeremy