Don’t let people get into arrears. Where money concerned people can get very emotional and things can quickly get out of hand, it difficult when it’s a club as they’ll know her both personally and as Treasurer – they need to know the Treasurer version of her is all business and it’s nothing personal.
At least there’s no staff so all the transactions will be straight-forward. Get receipts for everything, keep cash advances to a minimum and if you give any then make sure they are signed for so everyone knows where they stand.
Go for a little & often approach on keeping on top of things, it’s way easier to reconcile a weeks worth of transactions than it is a month.
Oh and keep a good supply of wine (or whatever her tipple of choice is) in the house.