3K a day is definitely possible. I set all my characters on their longest quests overnight, and then during the day, I try to get all the event currency characters to go out every 1-2 hours while I'm at work unless they have a required event quest. When I get home, everyone goes on their shortest quest. Once I get home and get all my chores/dinner/etc. out of the way, I try to keep the characters going every 1-2 hours except Goofy and Jessie, who, combined, can earn 200 coins an hour by repeatedly going on their 6 min quests.