[quote=Turtlicious]
That's going to be hell, you're not going to get Soapstone help which you really need, and you won't be able to summon people who will just wreck fights for you.
[/quote]

Agreed.

Invasions are not [i]that[/i] common in the game. Though I will say I experienced most of it in the first few levels. 
Messages on the ground, when they're not trolling, are extremely useful and build up the collective knowledge you need to know to get through an area or get a good item, shortcut, etc.

Furthermore, there's a couple bosses that almost everyone will go through the pain of finding an online partner to fight, because they're that difficult to beat.

[i]Can[/i] you play offline? On my PC, the game refuses to save unless I'm online/have a GFWL account.