Good luck to you.
After you've gotten the fundamentals down, if you have some coding skill or a good coder on the team, you could consider implementing some of Oblivion/Morrowind's features that really helped to enliven the world (being able to pick all kinds of things up and pick pockets etc). That however is a tall order. Do like others have said and take things one step at a time.
It is ok to start work on quests, but it will be hard to finish them until you've got all your other basic features into the mod. Making "epic" quests is definitely not an easy task.
I would recommend looking at the tutorials on these forums and acquiring some other modding skills. Developing more skills will really help to speed your mod along and will provide a very solid foundation for a modding team.