Boon docking through Canada is limited but the Provincial Parks provide a good cheap alternative in Yukon, and they provide free firewood. The ones in BC are fairy pricey.
In Alaska you can pretty much pull off and camp in any spot that is large enough for your unit and there is not a "NO PARKING or NO CAMPING" sign.
Re the Dalton. We drove it in 2005, 2009, and 2013. You can see our trip logs and photos in the website listed on my signature.
We are currently planning another trip in 2017. Will do the Dalton again. The opportunity to see Musk Oxen in the wild is a great attraction to us.