If I mailed in my state tax return (Hawaii) what's an ETA of when I should hear back if it was accepted or not?

when you mail a return, there is never confirmation that they got it. That's why if you mail a return you need to use a method where you can either track it or get proof of delivery.  figure it's going to take 9 to 10 weeks to be processed once they get it. if they get it.  however, you may be able to check its status on its website 4 to 6 weeks after mailing.