This girl I've known for a while hit me up recently and wants to hang out

I've known her for about half a year at this point, and we have some history:

Sorry for the broken link, forum won't let me post it. Just copy paste.

I ended up going to her birthday party, as mentioned in that post, and it was fairly uneventful.

I chatted with some other girls I knew and hardly talked to this girl. At one point she sort of stormed off while I was chatting with this chick. I haven't initiated contact with her since.

She did message me a few weeks after that party and asked if I wanted to go out rock climbing. I told her no, I'm busy, but that she could come over and we could eat and relax. She said blah blah, that doesn't make sense, that would take just as much time as climbing, blah. I said that wasn't going to work, wished her well, and left it at that.

At this point I'm a bit fed up with this girl. She had her chance to be with me and she had her chance to be friends with me and it didn't work out. Oh well, move on. And so I did.

Fast forward to a couple days ago and she messages me again, asking what I'm up to, blah blah. I keep my replies short and to the point because what does she want? She asks if I'm around for the summer, I am, cool, let's hang out. Sure. She says here I don't have to if I don't want to. And I end up saying well, hey, we'll go grab lunch some time, because I'd feel like an asshole just saying 'no I don't want to see you'. And that really wouldn't be true anyways. I mean I really have nothing to lose from lunch.

Now I have lost of a lot of respect I had for this girl and I'm a lot less interested in a relationship than I was before and even less interested in just friendship as she hasn't brought much to the table. In fact I'm mostly only interested in sex.

So, to make a long post short, how can I hook up with this girl? I'm thinking just build sexual tension when I see her and eventually ask if she wants to come over. If she says no, whatever, I'll be on my way.