Per DisneylandToday: "After they leave for San Fransokyo, it's hard to say when they will make a return"
That said, I can't imagine Baymax meeting and greeting away from the Starcade or some other setup. That's because Baymax regularly has to go into a back room to recharge or reinflate. When we met him and Hiro in November, it seemed like Baymax had to go "recharge" every 20 minutes or so. So, Baymax will never be a wandering character and can only really meet and greet if Disney sets up some location for him.