Asking about the less pressured LO tribs is like asking about someones favorite wild trout stream. Everybody would like to find big fish without the crowds.
NYS DEC website is a great source of info - can access where fish are stocked and where Public Fishing Rights are. The best guides IMHO are the Sanders Guides. Guide I for western NY is current. Guide II for the Finger Lakes (covers Wayne, Cayuga, and Oswego counties) is a little dated, but is still good. Then get out your DeLorme Maps and start exploring.
A lot of scouting and walking can get you away from crowds. The smaller, less pressured tribs have the fish come in and out more quickly. Every little trickle can bring in a few fish if the water is up for a short time at least. The bigger streams, like the Salmon R, will have some fish somewhere for 8 months of the year - that is why they are crowded. Then there is walking. The most serious trib fisher I have fished with walks up to 6 miles of stream a day. Look for streams where the PFRs let you get at least a mile from the road. A walk usually leaves the crowd behind. In streams with short fishing stretches, like Oak Orchard, it is hard to find peace. Even the Salmon R has spots where a good walk can leave you with a lot more breathing room.
For steelies the cold weather of late season and the smaller tribs give you more options. If you are looking for kings then crowds will be real hard to avoid - but a good walk can do it sometimes.