Do these bolt up to the factory mirror mounting points?

Yes, these mount at factory rocker and door locations — no drilling or frame modification needed.

Will these work with my OEM power mirror wiring?

These are manual-only — they don't tie into electrical systems. If your van came with power mirrors, you'll disconnect that harness and use the manual adjustment lever instead.

How much farther do these extend compared to stock mirrors?

Extension distance not specified — test-fit on your specific van before finalizing installation to confirm sightline improvement for your hauling needs.