The upper Colorado is a good place to practice your rowing. From pumphouse you have about an hour before you hit the first rapid, needleseye.
Get comfortable getting where you need to be, and learn how rowing moves the boat differently than with paddles. For me, the big difference is with paddles you put your back to the wall, rock, hole or whatever you are wanting to miss. When rowing I face it so I can pull away.
Needleseye can be intimidating at high flow, but hit the line right and it shouldn't be a problem. You should be comfortable fully shipping your oars in case you misjudge, but really it is a straight shot. Just line it up right. Try not to ride the rock in the middle, it will spill your beer.
The next rapid is Yarmony, at this level there can be a hole in there that can flip the unwary, and as noted above, go left then work back to the right to stay off the wall; it can bite if you aren't paying attention. Plenty of room to maneuver though.
There are bridges. You need to be very aware of the middle supports; at this level the current is deceptively strong going into the supports and you can find yourself firmly WRAPPED. Just don't get lax with them, and stay well away from them.
Enjoy. I suspect your biggest problem will be the traffic jams on the river.