We are a family of 5.  Our girls will be ages 6, 8 and 10 this summer.  We've done a BWCA trip before, but this summer are planning to go to Quetico.  We went with grandparents last time, so it was easy to split up the kids in two canoes.  This year we want to go just as our family.  Two canoes is not an option since my wife is not a strong stern paddler, and the kids are just too small to handle bow paddling on their own.  I want to put all 3 of them in the middle of a canoe.  I was thinking about an 18.5’ 3-person, with the two little ones sitting side by side in the third seat, and the older one can sit on a pack in front of them.  But the more I think about that, I don’t think it will work.  Too much gear (at least 3 packs plus misc.) and too many people.  It looks like Wenonah makes a Minnesota 4 at 23 feet long.  Anyone have a suggestion on how I might be able to safely accomplish this?

I have done such a trip (only with 4 boys) and rented a MN 4.  It is a barge but is sufficient to the task of travel.  It weather-veins and it can be difficult to keep it on track in the wind but I had a 15yr old in the bow.  It's impossible to fish out of when it is empty.  So, if you're just traveling and hauling gear from place to place I think you will find it sufficient.  Can the 10 year old kayak alongside maybe?

This looks like a fun way to go with a family.  Just no creeks!

"I can't imagine trying to maneuver a heavily loaded barge like that without 2 STRONG paddlers minimum.
You get caught with weather change in open water with only ONE strong stern paddler, I can't imagine things going well for you."

I agree to a point, but not totally with this.  When I used to work as a canoe guide, I occasionally was in the stern of a 24' Voyaguer canoe - usually had 3 or 4 other people (novice paddlers) and maybe a ton of gear - boat was 5' wide at center and weighed about 400lbs empty.  Once you got that mass moving, momentum worked in your favor and in strong headwinds it would outperform tandems easily - the same wind blowing a light and heavy weight will have more effect on a smaller mass - visualize a golf ball and a ping pong ball set in front of a fan - which one do you think will get blown the farthest?  Building up and maintaining momentum is the key.
Paddling a MN 4 with the o.p's family, I'd have the two older kids paddling on the same side as mom, and definitely "trained' to paddle in sync with mom, stroke for stroke which should offset a strong stern paddler. and have mom learn a bow draw and sweep to help steer that big boat from the bow.

Bohnsack, I think you're on target with the MN4.  If this is the way you have to go to make it work, it beats not going.  You can plan your route to take advantage of the big boat's strengths, ride out the weather if too windy and stick closer to shore to avoid getting caught in the open.  The MN4 has large flat center seats (if renting, double check with your outfitter for the seating layout). Most outfitters will have at least one.  I'd go with mom up front, 10 year old next, the younger ones side by side third seat, you in the stern.  If that doesn't work out, you could put one center sitting on a pack.  Ditto what MM said about mom and front steering strokes.  You should easily be able to fit 5-6 large packs in there too.  Smaller packs work better so the younger ones can be more help on portages.  If fishing is in the cards and it's less than calm, throw a few packs in sitting low to help stability and lower the profile a bit.  Good luck with the planning.

pd

Glad things worked out for you 
Hope you took some good pics to post, maybe one with the canoe loaded?
Others might benefit from your first-hand experience.