For the mall, I managed to have a hold a 5 minute conversation with her beforehand. Then I mentioned that I was going to the mall and asked if she could come, which she couldn't, of course.
For the coffee house, I left her a message and she texted me back with the homework excuse. Admittedly, I waited until the last minute (2 hours before it started)
I didn't want to sound like I was desperate for her attention, but as >>2 and >>6 said, she didn't venture for a better time/date.
Oh well, back to the bookstore I suppose.