I would prefer to start with one of the CK games perhaps 3. Here are my broad general intentions for the campaign. The mega campaign will not start until all parts are resolved. Each subsequent thread will list the choices already made so there is no confusion.

Once I have decided on a choice (whatever the topic of the thread is), I will move on and create another thread that deals with another aspect of the campaign. That is because this is going to be done incrementally, so the discussion in the comments can focus on deciding one aspect of the mega campaign at a time rather than all at once. Now, you may have noticed that the title of the thread says 'Part 1'. That's why I have created this thread, in order to figure out the details of my mega campaign. There is a lot of information out there on mega campaigns that is contradictory, confusing, and hard to sift through. I have many of the paradox games and am willing to spend a bit of money to get whatever extra games/expansions are necessary. Hello! Lets get this started by me saying that I am very interested in doing a mega campaign.

How to play stellaris campaign