I am going to Qld with the kids for a couple of days before Christmas, getting back on the 22nd, so I have the same problem of needing to be at least a little bit prepared prior.
I decided for a dessert to make a raspberry ice cream cake, just soften a 2L tub of vanilla icecream, mix in a bag of frozen raspberries and a couple of roughly crushed meringues, and freeze in a lined cake tin covered in cling wrap. Then when you are ready to serve, turn it out onto a plate, and top with lots of yummy fresh raspberries.
Easy to do while I am busy with packing and looking after the kids, and then easy and quick on the day. It also looks pretty!