Question about guild quest

Is there any way that a 3 man guild do medium or larger missions?

 

Try it and find out

But it usually takes either very well geared veteran players, or 5+ in my own opinion.

 

yeh but i cannot start the quest thats my problem, when i try to start it, it says "There is a guild level restriction"

 

You cant start quest for larger scale guilds. Only way to do better quests is to grow bigger. But still with small qiest you can level up quite fast.
Spread between 3 channels and each of you can solo small gathering quest for logs/wood.
It will take you around 1 hr to finnish all 10 of them.

 

Thing is...you actually need 30 players in your guild to be able to do those medium guild quests, and then I dunno how many for large guild quests but a lot I guess.