This requires a lot of judgement about your industry and company, but to quit after a promotion might be taken badly if it wasn't discussed the right way with the new boss first. Do you see a possibility of the promotion conversation being your opening to say you want to take XXX time off and want to come back and have a path to that VP job?
If you do get the VP job and quit, don't *worry* about being leveled out of jobs, do something about it. When you do your job search, send out resumes both with and without the promotion too see how they hit. Since you are on this board, my assumption is you have your shnowzers together and can hang out for a bit while the job search runs its course.