You've got the basics down already, for the most part. All the Caravan quests can only be done offline, solo.
It's recommended you proceed to at least the 3* caravan quests before trying to take on the gathering hall quests also.
Wow, thanks! Good to know that I am on the right track.
If I don't have anyone to play with, or my schedule doesn't permit, is it worth attempting the Guild quests on my own, or should I just stick to the Caravan quests?