How much you can charge depends largely on experiance and the company... You say the past SM was a dancers mother... Based on that comment, they may not be able to afford equity rates.
Also - by community, are we talking amdram-esq community theatre? If so, are professional rates really the correct entry point - no matter how much experiance, on paper, work in an amdram theatre is probably not able to justify full rates...
And another point - will it be stage managing as in typical stage managing, or will it be "Back stage manager/calling cues/doing tech without the rehearsal process"
Best bet - ask what they think is a reasonable pay - see what they have been paying. Before you go to the meeting though, make sure you know how much you need to make to keep the job from costing you money - so that includes transport, meals, time lost from primary place of employment, time lost from personal time etc. Then work out how much you want to be ahead... That gives you a base figure and an acceptance level.
Three things can happen, they can give you a figure greater than your acceptance figure. Accept the job. They can give you a figure between the base figure and the acceptance figure, consider it, try and get perks etc. They can give you a figure bellow your base figure. Don't accept... A job that costs you is not worth it.