L.M.
I agree with the other Moms who have chimed in already. I always do a combined party for my daughters since their birthdays are very close together. I usually get a few balloons, and sometimes (but not always) a couple decorations. Easy food that works for kids and adults is good, with lots of fresh veggies and cut up fruit are always a hit. I don't ever worry too much about having organized entertainment because the attendees are family, and mostly just enjoy getting together and chatting! And it makes for less stress on my part.
Hope your party goes well!
L.