Is it safe to cross the Canadian border with a J1 visa and come back on a B1 visa? I have heard some stories about having to bring proof that you are leaving the states to your home country after. Also about people who were told to stay in Canada for a night.
It is not an issue to leave on J-1 Visa and re-enter on B-1 visa.
You can review the J-1 Website from the State Department on the subject of 2 year home country waiver.