Hey Tony, sorry I missed this for a while. Sometimes I don't get a notification of new posts for some reason.
Unfortunately the printing capability in TopoFusion is pretty limited. You'll get a better fitting map if you switch to 'landscape' mode on your printer. But there is no 'fit to page' option.
My best suggestion is to instead use the 'Export View' function to create a high res .bmp or .jpg export, and then use image software (even the Windows photo viewing software will work) to have it print to a single page.