There is nothing more comfortable to travel in than a van built to your specifications. I’m talking about a Sportsmobile. While the VW Eurovan would also be nice, they don’t have them here now. I think you can still get one in Canada though.
The nice thing about a Sportsmobile is you can get one outfitted with exactly what you want/need. With two small kids, you might elect to have a toliet and fridge for comfort/convenience while on the road, but not the stove/microwave. Maybe you’ll add a TV with satellite and DVD.
Naturally, you can camp out of a Sportsmobile. Having their popup top supplies extra bed space. Add an awning and you have an outdoor living room!
Most vans will tow a small (under 3000lb trailer). That lets you store extra clothes/toys/supplies without the hassle of a travel trailer. This will give you lots of options for overnight accomodations – like camping at our national parks (nothing as great as camping at the Grand Canyon after the summer crowds are gone); renting a cabin at state parks (NY State has some fabulous state parks); or, staying in a hotel when you are in urban settings.
I don’t work for Sportsmobile, but I own one and love it. Working with them here in Austin, TX was a pleasure! (www.sportsmobile.com). They also have facilities in CA and IN.
Good luck! It will be a fabulous adventure!