I really believe having a small explanatory text for each "quest" is fundamental. Personally that was just what mentors were supposed to do in my opinion: tell newbies why what they are supposed to do is important. "Go there click politics -> take an estate" is boring and annoying for someone joining a super complicated game like bm. Explaining what estates are and what they entail is meaningful. Maybe the quest can point to the wiki but it should be, at least to a certain degree of deepness, self consistent.
Thinking about the branching Tom mentioned, just on the top of my head one could have 2 quests once settled in an estate: serve the realm by being assigned to an army and going to the capital, or improve your home region through police or civil work. Once assigned to an army one can have 2 branches: take a scout and scout a border region, or increase your unit size and reach a certain cs for instance.
I do not believe it is so strictly necessary to give material rewards for finishing the quest, other than unlocking the new donations from the family. This is not world of warcraft. The purpose is to teach the games to newbies, the reward should be an increased understanding of the game itself, and perhaps the opening of new options (such as scouting if you pick up a scout, police work once you switch to police force etc)