Visiting assistant professor position vs Post-doc position
If your goal is to get a TT job at an R1 university, you would be a lunatic to choose a job with 3-3 teaching load with no research support over one that is research focused.  I'm extremely confused about why you're even asking this question.

EDIT: To specifically address "if getting a VAP job for a year would enhance my resume (to be able to compete for a TT position) over having a post-doc,"  the answer from everything I know is a resounding "no."  It will just look like you couldn't get a decent postdoc.  Maybe teaching 1 or 2 classes if you can arrange it with one of the postdocs would be a net positive, but the VAP job you're describing would be a disaster for your research, and that's what gets you the sort of job you say you want.  Maybe you're extremely productive and in a very in demand field, but if your research is good enough that you can take a year off (effectively) and still get a TT job at an R1 university, then you can potentially get an even better job (or be in a better negotiating position, or be in a better position to get tenure) if you keep your research up for another year.  Certainly very few people are so productive that they can afford to take such a huge risk.