I have had good luck on the lower section of the Poudre between picnic rock and gateway park. It's close to home for me so I can get there quick. The north fork at gateway park is also good but it gets hammered. there are some big browns in there though. I have also gone up to indian meadows (about an hour up the canyon just before the little town I cant remember the name of). I think this area gets hit pretty hard too. Indian meadows is C+R flies and lures only. Gateway park/ north fork are C+R as well.
I've really only fished the poudre in the summer with fly gear (I use spin gear in the winter) And I really only fish nymphs...So I've had luck with flashback hare's ears, zug bug, prince, pheasant tails and copper johns as well as muddlers and wolly buggers. I don't know about this time of year. I hope this helps a little.
If you stoped at gateway park you should have gone up toward the res. and there are all kind of bows and browns in there. They love haresears this time of year also midge pupa, Don't give up on the poudre it is an awesomw fishery.
In the colder months it can be hard to spot fish. How far up did you go? I would recommend the river above Rustic. From the town all the way to where it heads into the park is good fishing.
I wouldn't spend to much time in one spot either. When I first started fishing the poudre I would park the car and then just start upstream. Not staying in any place longer than 15 minutes if there wasn't any action. Some times I would end up quite a ways from my car. But you cover alot of water and you find where the schools of trout set up shop. One time I stayed out way to late hiking and fishing and a nice fellow gave me a ride back to my car. He clocked it at 11 miles on his odometer. That hike back would have sucked.