I hope you didn't answer his personal questions. When someone starts asking me questions that I feel are personal, I become very vague with my answers or simply say, "Oh, I don't think we need to talk about that." With a smile on my face. And then I immediately change the subject.
So, what do you do now? Well, unless he makes anymore advances, I'd move on and not say anything. If you say something, you could stand to pi$$ off a guy that was unrefined enough to outright ask you for sex. If you don't say something, he might just think you're not interested and move on to his next potential score. The second option is definitely more preferable.
Now, if he gets a little freaky-deaky and makes another proposal, simply say, in a polite, neutral tone of voice, "Your first offer made me uncomfortable, and now that you've done it again, I'm even more uncomfortable. I'm sorry, but I'm not interested in sex with you." If he has any decency, he'll feel bad for making you uncomfortable. And this response also makes it clear you aren't interested. In other words, "Dude, do not ask me again, or things could get ugly. You're freaking me out."
I'd keep your eyes open for anything unusual. Get a can of mace or some kind of item you can use as a weapon, such as a metal fingernail file, a "persuador" (a 4-inch blastic "keychain" that has many uses), or even a fine-tip ballpoint pen. These things can be the difference between "getting away" and "getting pulled into the van".