I recently started playing MH4G, my first real foray into the series, and I'm a little confused by the structure. I've finished all of the 2 star quests that were available from the lady in Val Harbour and now I'm not sure what I should be doing?

I've unlocked another village but it seems like it's for high level quests that arnt accessible to me yet. Should I be going to the guild hall and doing the quests from there? I went online for a brief time yesterday for the first time and joined two others to take down a Great Jaggi. I've already killed one of those by myself but it was much quicker with two other people wailing on it.

So, should I be in the guild hall? What's the difference between guild hall quests and ones from that lady? What are these expeditions? Thanks.

In MH4, the game takes you down the path. If you finished all 2*, then look for anyone with a yellow quote bubble over their head. That'll open up things further. If you're referring to unlocking Harth (which is the next city), then that's where you should be going since I think that's where 3* starts.

Guild hall is typically to do multiplayer, which is a different progression from solo (aka you'll still have to do the story).