We just spent the last 8 months touring around South America as a family. Kids are 6, 9, 11, and 13. I feel I basically traded a boring retired year without kids in my 40s for an exciting year traveling with the kids in my 30s.
As for young kids, we did a trip to New Zealand with a 1, 3, and 5 back in 2016. Honestly I feel like we missed out on a lot of stuff because we didn't go far enough beyond the parking lots. Lots of short hikes but only saw a fraction of the country. Makes me want to go back for the cool backpacking trails when they are older. Camper life is great, but I've found slightly older, no diapers, can hike 6-8 miles is a minimum. I'd still do that month off you're planning, just realize you might come back to places later.
For later on, 1st grade or older can do pretty much anything. Go for it!
We're Roadjello on instagram.