OP has stated he does NOT want to attempt taking handgun into Canada.....
Best advise given is to drop it off at a gun shop prior to entry into Canada and then have that gun shop forward to a gun shop near return point into USA.
Gun shops close to Canada Border handle this and are quite familiar with it.
OP also stated he would be traveling to east coast so the comment about NY is valid somewhat.......
Federal Law known as the Firearms Owners’ Protection Act:
"Permits the interstate transportation of unloaded firearms by any person not prohibited by Federal law from such transportation regardless of any State law or regulation."LINK