The home party - have a theme dress up party (the kids can come in their favorite costume, favorite superhero, favorite princess, etc.). Have the party from 2:00-4:00 so you only have to provide light snacks, cake and drinks. Keep it on the smaller side (maybe 6 kids) so you can keep it under control (I don't know how teachers can do it). Have them decorate a brown paper bag with crayons, markers, stickers, etc. Then play a game or two (musical chairs or pillows is always fun or hot potato), then do a craft - give out small prizes at each activity for them to fill their brown bag (this will be their goody bag to take home).
Local playground or park - there are usually plenty of picnic tables or even covered shelters that you can use. Bring some decorations & balloons to make it look festive. Order pizzas (you can even have them delivered there) and have cake. If there's a playground, you already have automatic fun playtime built into the party. Get a pinata and fill it with candy/small prizes - give each kid a bag and tell them they can take 5 things when the pinata breaks (so as to avoid a frenzy when it does). You can even hire a babysitter to bring with you to help facilitate the games. Maybe she'd even be good at face painting or you can give it a try - kids love all that stuff. Get some removable tattoos and do that. Fun, fun, fun!
The "almost sleepover" party or "1/2 over"
- this might be more fun for the girls. If you're not quite ready for
sleepovers, this can be fun. Have the party from 7:00-9:30 and the
girls come in their pajamas. You can make your own sundaes with tons of
different topings, then have the girls do a craft and then you can
always pop in a movie and have popcorn and drinks. They can even bring
their sleeping bags/pillow so they can all veg out together. Or put on
some dance music and they can boogey on down.