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[Game of Thrones] What exactly was Rhaegar planning?

In S7E5, we discover that Rhaegar had annulled his marriage with Elia Martell to marry Lyanna Stark. Afterwards, presumably, things did not go as planned (with him dying on the Trident, Elia raped and killed, Rhaenys stabbed to death and Aegon's head smashed against a wall, and Jon living as a bastard in the North).

So...what did he expect would happen? He leaves Lyanna at the Tower of Joy, goes off to the Trident, defeats Robert, forces the rest of the rebels to bend the knee...then what? 

* What is he going to do about Dorne (who will be *beyond* enraged when they find out about him annulling his marriage with Elia)?
* Lyanna doesn't know that her father and brother were burned alive. How does he figure she will react?
* His loyal vassals (the Tyrells, the Martells, the Crownland lords) are going to be pissed that the Starks' reward for rebelling appears to be a royal marriage. How does he plan on dealing with that? 
* Is he going to retroactively declare Aegon and Rhaenys bastards? If not, who will be his heir - Aegon, or Jon? Is he prepared for the greatest Targaryen War of Succession since the Dance to break out?
gpt
The most important thing to understand was that Rhaegar was big into the prophecy of the Prince that was Promised, and believed that said Prince was going to be his son.

I think he'd probably have Aegon and Rhaenys legitimised, to keep the Martells happy. Aegon would officially remain the heir, and he'd try to raise baby Jaehaerys to be the Prince that was Promised. The Prince is supposed to be a champion, not a ruler, so his being runner-up in the line of succession doesn't matter to Rhaegar.

Barristan Selmy seemed to think that Rhaegar was planning on doing something about the Mad King once the rebellion was dealt with. Presumably he'd have him locked up "for his own safety" and then engage in some intensive diplomacy to try to end the civil war.

He could (accurately) blame the deaths of Brandon and Lord Rickard Stark on his dad, so with that and a marriage to Ned's sister he might be able to talk the Northerners into peace. Robert Baratheon would be a bigger problem, but with luck Jon Arryn and Ned Stark would be able to talk him round. He could be bought off with the promise of a suitably wealthy and beautiful bride - and Cersei Lannister is still single, that'll probably work out great.

After that Rhaegar can usher in a new age of peace, reconciliation, and brotherhood, at least until the White Walkers come and kill everybody.