B.,
I am all for "at home" birthday parties. I have 4 kids age 2-8 and it's all we do. My son just turned 7 and for a craft, I gave them a bag of colored pipe cleaners and told them to make something. I was amazed that they were totally entertained for about 10-15 minutes. They made superheroes, battleships, you name it. I think girls would do just as well making what they like. 6 year old girls will also like glitter, puffy pom poms from the craft store, scented or glitter markers, etc. (Look for 40% off coupons from Michaels or Joanne's Craft stores.) We as parents try to come up with these crafts that the kids have to do a certain way and then the kids need so much help that the parents end up doing it for them. I am all for giving them supplies and tell them to do what they want.
A game we play that goes over really well is called "Don't eat my ___" (Insert theme appropriate answer. Maybe "Don't eat my surfer" or "Don't eat my beach bum" if that's your theme.) Print 9 small pictures related to your theme and glue them onto a piece of construction paper or cardstock. Put a piece of small candy or popcorn onto each piece. Have one child leave the room for a moment. Point to one of the theme related pictures so everyone except for the person who's "it" sees it. The "it" person comes back and picks candy off each picture and eats it until she picks off the picture you pointed to. Everyone yells "Don't eat my _____" (again insert theme name) and she stops. Start with a new person as "it." It seems like a simple game, but I have seen kids play it 15-20 minutes, then ask their parents to make a gameboard when they get home from the party.
For several parties, I have gone to the local library to get CDs so I have music to go with my theme. Freeze dance or musical chairs are fun. If you are worried about hurt feelings over losing, I only keep out one chair and whoever loses gets to work the CD player on the next round. I also pick up a ton of children's books that match my theme. They can look at them when children first arrive and we are waiting to start or when children are waiting to be picked up. It mostly stops them from running around like wild banshees, but frees you up to greet / thank guests. I also have one picture book story I read during the party. Birthday parties can quickly get too rowdy and having a story read midstream brings a quiet moment to the chaos.
I always do gift opening right after cake and ice cream. Kids finish eating at different times and you need the activity right after that to be accommodating. Putting a craft right after doesn't work because your table isn't free and doing a game right after doesn't work if you need all the kids there.
I would limit the party to about 90 minutes or 2 hours tops. Their attention span is short and you will need to have something new planned for every 10-15 minutes. I wouldn't advise playing with the new birthday gifts to be on that list. Too easy for a new gift to break, parts get lost, jealosy issues, etc.
If your daughter has a favorite babysitter, invite her if you think she would like to help you host. If you have friends with a daughter who is almost babysitting age and wants practice tending kids, invite her to help you with the party. Or you could ask to hire their help if you feel that's more appropriate.
Good luck. I hope it's a great party!
S.