The Treaty of Tilsit actually allied Russia to him and encouraged Russia to war upon the British and Swedes which is why the Napoleonic Wars would go on. Alexander at the time was not interested in arevenge war he practically in love with Napoleon. The man was very caprious. One moment it was, Yeah Napoleon, the other it was Napoleon=Antichrist.
Napoleon could continue to Poland, Benningsen would have lost command to a different commander because of Friedland. But i doubt a commander cautious enough within the army had the prestige to be given the command. And I think Kutusov was in Russia, because I doubt Alexander would ahve allowed him in his presence after Austerlitz (which was really Alexander's fault). So Nappy would continue and beat the Russians some more and liberate Poland. After that sues for peace and gains a free Poland. But with a free Poland, comes more Napoleonic Wars. Austria cannot have a big free Poland, considering it owns considerable Polish lands, Russia won't stand for it, Britain still has cash, the Bourbons in Italy still want Naples, and so on.