Throwing a surprise birthday party..... how do I bring the b-day girl to her house for the party? ?

I'm throwing a surprise birthday party for my sister who is turning 21. I'm throwing it in our big backyard in June. How do I get her to our house already dressed up and beautified while she's thinking she's going somewhere else? I don't want her to see the big tent either. How would this work? She has a boyfriend... could he help with the transportation maybe? I've never done a surprise party before. And my mom's helping but I just want ideas from people who have either experienced this themselves or have been to a surprise party.