I am looking for a canoe to fit my entire family in, which consists of 2 adults, a 12yo, a 5yo, and a 3yo. We will not be packing a lot of gear. We will be camping in one place and just using that as home base, just taking the canoe out on the lake to fish and to find a place on the shore somewhere to picnic. Our total combined body weight is less than 680lbs. 2 people will need seats and be up high to paddle, but the rest of the people will sit in the bottom on padding. What size canoe do you think we would need? I noticed that the Old Town Discovery 174 can hold like 1000lbs and is 3ft wide. Do you think this would work for us? What about a 17ft aluminum like Alumacraft or Grumman? We are OK with the 3yo sitting in the adult's or 12yo lap but would not prefer it. Also, can a canoe be strapped to the top of my Toyota sienna for transport?  Any help would be very appreciated!

Thanks in advance, Kristin :D