Shannice Godkin, 18, Sarah Benioni, 18, and Tee Felise, 21, have been parked up since 8.20pm on Monday.
Godkin says they headed to the venue almost as soon as the sign went up that they could join the queue.
"As soon as the post went up that the queue was open, we came down to have a look and ended up staying."
Godkin says the prize of one year's worth of doughnuts was the drawcard for her.
Tee says their two nights' stay is far from overkill.
"We had other people come [in the middle of the night] and then they left."
The large store, which includes an onsite factory, will churn out about 78,000 doughnuts a day.