If they still had Gandalf...

[Glirdan]

Ah, but see. That is where you are at fault. He did know about the Nine coming forth. He learned about it from Radagast, before he went to see Saruman. He would still add haste to thier journey and if they did get attacked at Weathertop, I think he would have somehow have stopped the Witch-King from stabbing Frodo. Thus, they wouldn't lose as much time as they did when he did get wounded. They would have had the Council sonner and probably would have left and yes Boromir would still have joined the Fellowship.

As for him going to the Prancing Pony, that is possible, yet I think he would have felt safer if he went to the Shire and told Frodo that they had to leave straight away. They would have reached Bree sooner, before the Nazgul even reached the Shire perhaps. They still would have met Aragorn and all six of them would have left for Rivendell. And seeing as they left early, there would be no fight at Weathertop and they would have reached Rivendell even sooner.

Now this raises some more questions, does it not? The most crucial would be "Would they have the Council of Elornd early?" What do you think?