JQuery Radio Button / Checkbox Flow

Question

I've got a set of questions that when selected displays another set of radio buttons for the next question (a show / hide system), what i'm having trouble with is that at the end of the questions (only 3, but on one step there's a skipping system) i need to post to a specific url depending on what the user has selected, so the href needs to be dynamic - essentially as it calls another js file i have no control of and passes in a unique answer code.

I'm really struggiling to think of a way to make it fool proof so if the user starts back tracking the url will still be updated.

What makes it more difficult in my head is that at the end there's a checkbox too that needs to be considered.

Any help would be hugely appreciated.

Thanks,