I can always get the k-close and continue building more and more attraction through the night but when it comes to the part where I want her to come back to my dorm room and go father I never know what to do/say or act. One time a just said let's go back to my dorm room but she was a 6 and she tried doing so many other things before we finally went back to my room (seemed like she didn't want to go but these was nothing else to do). So this last time I just hesitated and made it seem like my room was occupied. What do I say? Besides "Let's go back to my room" or "would you care to spend the night in my room" what can I say?

3 things wrong with this: "Would you care to stay the night in my room?"

1. You are asking, don't ask. Suggesting "we should..." or ordering "let's go..." are much better and more dominant (alpha male).

2. You are giving her an invitation for sex. Even if she really wants to have sex, if she knows for sure that this is what you are pushing for and there is no other reason to go to your place, most likely her anti-slut defense will kick in and she will say no. Women want sex to kinda just happen. Weird, I know.

3. You are being too polite and sounding like a wuss.

So, reconstructing, start with a "Let's go..." or a suggestion "You should come back..." "...to my place..." now give her a reason to come back other than sex "...and check out this [insert interesting thing in your place]." Or "...and grab a bite, you look hungry."

You get the idea.

One tip that I remember from Style was that you should always bring your target to the place where you’re going to f-close at the beginning of the date for a little while. The idea is that if she sees your dorm in a non-threading manner first and she’s been there without being seduced, she won’t be so afraid to return later. Maybe you should have her meet you at your dorm before you go out, or have her over during the day with some of your friends, so she’s not so scared to go in. Whatever it takes, make her feel comfortable being in your dorm first. Then when you want to f-close she won’t be so scared of it, it will be more like a neutral hangout in her mind rather than a sex den.
Also if you want to get her to your room, just make up an excuse to take her there. Tell her you have a cool movie, you two could watch. Tell her you have a book you want to show her. Tell her you have beer in your mini-fridge. It doesn’t matter, but if you ask her straight out to go up to your dorm or ask her to spend the night, her anti-slut defense will stop her from doing that.