What size canoe is good to go on a mini van?

Purchasing a canoe for me & my 12 & 8 yr olds. What would be the ideal size that I can still transport it around tot he lake on top of my dodge minivan?

Just about any canoe will fit on top of your mini-van if you have a decent rack for it. The factory roof racks on most vehicles are made to carry lighter loads than a full size canoe. Yakima or Thule are 2 of the more well known brands that sell aftermarket racks for canoes, kayaks, and bikes. The weight of the canoe is your most important consideration, because if it is too difficult for you to load,you will not use it as often as you would a lightweight craft. Happy paddling!