Mac, I'm confused. If I just wanted to watch a movie and hang out I'd invite my buddy (or buddies) and not some girl. But that's just me, so if you haven't shown a romantic interest in her prior to now you shouldn't have to tell her anything other than you'd like to watch a movie with her. If you have shown a romantic interest, nothing you can say will convince her you're not interested in ... well, you know.
If I read between the lines here, are you saying you'd like to get into her panties but without doing "the whole dinner and bar things, etc." Geez Mac, if you like this girl and want to spend some "quality time" with her, take her out and show her a good time. Spend a little money and who knows, she might be the right girl for you.