It has taken me roughly 50 hours of single player gameplay and about 5 hours of multiplayer gameplay, but I now have all of the current 54 achievements. It was a grind and often got very frustrating, but now that it is all said and done, I look back on the game with many fond memories.
I look forward to the three episodic pieces of DLC for The Tyranny of King Washington. Each should bring several achievements and I look forward to keeping my 100% on this game.
As a huge Assassin's Creed fan and an achievement hunter, thanks!