"I'm thinking of goin ahead and buying this one from dicks for 400 and then buyin the stuff to build my own. But any input would be welcome."

bad idea - buying a hog from Dick's, that is.  Why handicap yourself?

I'd sugest buying something like a Rx wen Argosy ($1100 msrp) - at 47 lbs, not too heavy for BWCA and a decent boat for moderate rivers.  Or Mad River Freedom Solo - msrp around $1300 - 55lbs.   If you want to build a boat go ahead, but this way you'd have a fairly decent boat to use in the meantime, and you could likely sell it for $750 or so a couple of years later if you want to get rid of it.

Or even better, keep an eye out on Craigslist and Paddling.net for other boats - used composite boats can often found for decent price. 

see this - Argosy for $850
  (You need to Login or Register

At one point, Bell was making Rx boats for Dicks - depends on what kind of boat you are looking at, but I don't think any of the better hulls were available for $400 - I definitely recommend not buying short and fat if you have any other options.