I don't go for the whole "Girls should not be expected to pitch in or lug heavy stuff" bias.
I understand that if a woman/girl is not particularly strong that they might not want to lug a P.A. around. However, that doesn't mean that they shouldn't be pitching in enough to help take down/set up.
In one of my bands, the drummer is a 5'6", 120lb-ish woman and she sets up/takes down her own kit. We help carry the parts in, mostly because we would do that for any drummer (They have enough gear as it is. We can certainly help where possible).
At school, there were a lot of female drummers. Not one of them complained about having to set up gear.
Your singer can get there a bit earlier, set up her mic, and do soundcheck like a proper member of the band. Then, unless there are pressing matters, she can tear down after the set like a member of the band. Regardless of whether they are male/female, they can pitch in somehow.
BTW, I am a gentleman as well. I pull out chairs, open doors, take coats, etc..... I just think that, if you want to be in a band, you act like a member of the band.