Helena doesn't have a main quest as such, she's just living life in Cyrodiil. However, she is trying to further her skills in Restoration so she can open the first hospital in (possibly) all Nirn.
I agree with Helena's thinking. Buffy's just trying to live her life as well. She does have what I suppose could be called intermdiate objectives (although she is easily distracted). It took great effort over a long time to get a good University education. She now seeks to improve her skills and recruit aid so she may help free Kvatch. I would not be surprised if she then becomes interested in trying to help Savlian Matius rebuild his city after that. Who knows? She has so many things she wants to do:
- Visit the province of Valenwood and learn more of her people that came from the Strid River Valley.
- Visit Skyrim and learn more of the ice dragon spirit that is bound to the paladin that travels inside her.
- Visit Morrowind because she has heard so much of it. The only other mystic archer she has ever met lives in Morrowind.
- Determine if goblins really are cave mer by trying to join one of their clans.
- Become a Knight Arcana for her guild of mages.
- Go on a cruise from the Imperial City to Anvil.
- Matchmake her friend Mazoga up with her friend Agronak gro-Malog.
Unfortunately, the list of things she wants to do grows faster than she can accomplish them.