An apartment is a great idea to give a bit more space. If you are not comfortable with a hotel babysitter, do your friends have kids and could they recommend any babysitters they know. FWIW I have used Agency babysitters and have always been very happy with them. If you did end up going down the agency path you could always meet them a couple of days before for a bit so you feel more comfortable with them. If you get a good agency, they do all the police checks, have first aid, etc, etc and are all checked out. I know it is a big thing to leave your little one with a stranger, the first time I went through an agency I was majorly stressed out but the babysitter we had was absolutely gorgeous, the reason they are babysitters is because they love kids. Good luck with this and I hope you enjoy the party.