Boromirs way?

[Gorwingel]

how did Bilbo get there? And what of his dwarf-friends, did they go there with him?

Are you talking about how he got there during the LOTR, or during the Hobbit?

Because if you are talking about LOTR he had been there before, so he knew how to get there.

Boromir had no idea. To me 110 days does not sound like too long of a time. It would be like me going to a city on foot or horseback, about a third of a way across the United States, without a map. And for me it would take awhile. And besides he most likely didn't run into many people on the road along the way. So he probably really became lost and that was probably the reason for the delay.