I couldn't open your link, but we did a 19 day road trip last year in a truck camper with a 7 y/o. Covered 21 states. Was it rushed? Yes. Did we see everything? Not even close, but we did get a quick overview of what the US has to offer. And we will probably never get the time to do it ever again. So go for it. You can adjust as you go and turn for home when you need to.
Google - "Lolo's Extreme Cross Country RV trips". She has a blog with awesome maps and routes. She and her husband live in NJ, so the times from NY are pretty accurate. Plus she packs a ton of places/stops into each trip.