R.G.
My husband and I pay $100 flat rate for an overnight when we go away and leave our two kids which we'd done many times. My kids are in school during the year or camp during the summer, so my babysitter is only responsible for the hours from 3 of 4 in the afternoon until the next mornng when she drops them off at school or camp. I think it's a reasonable rate since she's completely responsible for the kids during that time. Talk to your sitter, offer $70 to start and be willing to go up depending on what she's comfortable with. She probably has a number in mind. Have fun on your overnight!