How much is your Dad willing to spend? I assume he wants a smaller boat since he's looking for a boat for lakes and mild rivers. The first key is, does he want to fish like you do, sitting in the seat or pulling off and fishing from the bank? Does he want a stable boat.
I'd highly suggest moving up to a bigger boat, say at least a 10-12'. To get a small boat that has a good all around fishing package on it would be the Steelheader by Skookum
http://www.steelheader.com . Even mild rivers, you'll want to fish from the boat. At least with a Steelheader you can have a "pram" style cataraft. You can stand up with stability and fish a pocket without pulling to shore or trying to fish from your seat. If he has real money to spend, then he can move up to a Wing with a custom frame (Hey Os, does Wing make smaller then a 12' for anyone who wants a lake/mild river boat?)
If you have any more questions, please send me an email and can help you out.
Jerry
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You haven't lived til you've rowed a cataraft. Friends don't let friends run Outcasts.