Don't know about guides or the lower river, but the Kenai has a very long silver run. It's possible to catch them through the winter if you're one of those crazy enough to try.
yeah there is good numbers till Nov. and you can catch them even after that in good numbers till Jan or Feb if you wanted to. But just know the season closes Nov 1. And you shouldn't have any problem finding someone to take you fishing then. If you need help finding someone let me know I can point you in the right direction, or ask on here I am sure there is a lot of people on here who could help.
thanks guys...I was actually asking for a freind who will be up mid-sept and wanted to know what would be his best bet for getting into some late season salmon.