... preferably with a water feature at the end like a creek or lake?

My TJ will be ready to take the family on some adventures this next summer
(re-geared, camping/utility trailer, the right tires, etc) so I am rarin' to
get out of the valley and up into the central oregon desert.  Anyone want to
turn me on to some good trails that would get us into nice, clean, remote area
with good geology (fossils, etc) for kids, and maybe a creek with redbands in
it?  I can hear them sizzling in the pan now... mmm...

I'm thinking like a John Day tributary or something south of Bend, etc.  

Thanks!!

-jeff