Yeah, I've done a lot of daygame in bookstores.
There's no need to think you need any special opener for bookstores.
The book recommendation opener works fine.
If you're in the cooking section, you can go indirect with "Hey, what cook book do you recommend?" (Obviously, just change it for whatever section.) Just remember, after a simple everyday indirect opener like that, you have to immediately differentiate yourself from the average guys. So you can follow up with a tease like "Oh my god, you're totally fired as my personal book shopper. Its ashame, I guess I'll have to call the other girls. I had high hopes for you

"
OR just simply go direct: "Hey, this is totally random, but I thought you were adorable so I had to come over and say hi."
For daygame (actually, any game day or night, but especially day game) when in doubt, just go direct.
As far as an instant date, most bookstores have coffee shops inside of them, so you have the perfect opportunity for an instant date in a bookstore. When it seems to be going well and she answered a qualification question or two, just say "Hey, come with me real quick while I get a coffee." And lead the way to the coffee area. You can also add on "You gotta try the blah blah blah" as a little extra enticement to come with you.
AND you can also add on a false time constraint. Now, let me say that I almost never use false time constraints for opening (as they were originally taught in the Game) but they ARE useful for instant dates, especially when you're not totally sure if she's gonna follow you or not. So, as you're saying "Hey, come with me real quick while I get some coffee. You gotta try the blah blah blah. I do have to go in a few minutes, but blah blah blah" And keep talking to keep her distracted and engaged as you lead her to the coffee area of the bookstore, so she doesn't stop and think to herself "Why am I walking over here with this guy I just met?"
Also, keep in mind that if you go indirect, you have to start hitting on her as soon as possible. Like within the first few minutes. You don't want to have just a nice conversation that goes nowhere. During the day, girls will be nice and talk for a minute or two a lot of the times, whether they like you or not, so you have to actually show your intention:
"Oh, you do xyz? I love girls you do xyz. And you're cute. Listen, I will totally hit on you in the middle of this bookstore. I have no shame in my game"