Bicycle wheels are really lightweight but bulky.I used one of the baby joggers for making a garden cart for up and down my back yard trails which are pretty steep.I can easily pull two garbage cans full with about 80-100 lbs of maple leaves up them(getting almost that time again..
).The baby joggers have a lot of aluminum tubing and quick releases,and wouldn't take much for revamping to a canoe dolly..and usually an extra third spare wheel and tire,that have seen little wear and tear
.Keep in mind that they do fold up to fit in a trunk , back of an SUV,or back seat as they are.http://www.babyjogger.com/perf_jogger_lp.aspx
Burley bike trailers are another option..
They are expensive new but I've found them as cheap as $10-15 around here in the stores.I think there is one at deseret right now for $35(expensive!) or so with 12-16" wheels and tires.
My cart is actually a combination of a baby jogger and an old burley that were lying around.,just bolting parts together between the two because the burley had more space(held two kids) whereas the baby jogger held one. in the triangular frame.
here's what you need ...or an idea--->http://www.biketrailershop.com/burley-flatbed-bike-cargo-trailer-p-1304.html?gdftrk=gdfV22203_a_7c1234_a_7c8345_a_7c1304&gclid=CIiks53WhqwCFQVihwodGnioCw
This is what I used for my main frame style-->http://www.bikekidshop.com/burley-cub-bike-child-trailer-p-1298.html?gdftrk=gdfV22203_a_7c1223_a_7c8344_a_7c1298&gclid=CNrqqMvWhqwCFQYZQgodTy-hBg
I hadn't planned on putting the cans in,just leaves..but the cans are a lot easier.I have a couple big leaf maples that dump about 40 trashcans worth of leaves...throw them out in yard waste..