What was going through Rhaegar's mind when he finished watching the video of Sansa thanking him? What are his thoughts about the situation and Jon's involvement?
I can see the Lannisters/Baratheons (namely Joffrey and Cersei) being vindictive and trying to get back at Jon in some way so I hope Jon watches his back while in KL. I can see Cersei trying to press charges against him to spite Jon
Rhaegar is, above all else, so out of his depth.
He technically knew about the whole ghost thing for a while, because Lyanna tried telling him back when she was very young & in her whirlwind love, but he didn't believe her. Then his son comes in with sort of undeniable proof that they do exist and then does, in fact, find the body of the very person he claims to have seen as a ghost, and THEN that dead girl who's supposed to be a ghost but somehow isn't now (???) sends him a video confirming everything.
Oh and his son trespassed and broke into a cabin but that's like, the least of his worries.
The son that he has been trying really hard to reconnect/reconcile with is clearly struggling and definitely a little traumatized and the mother of that son is furious with him and she's very scary, and she seems to think something bad is going to happen to his son but he doesn't quite grasp what that is because the whole ghost thing is still very confusing to him.
The video was sweet, but Sansa is also the source of all of Jon's troubles right now, intentional or not. He doesn't hate her, or even really blame her, but he's not exactly sure yet about Jon's continuing involvement with her
As for Cersei pressing charges - I did sort of address this in the fic. The Lannister-Baratheons are going to have a lot more to worry about right now than him. And despite how petty she is, it would be pretty stupid to press charges against Jon for some trespassing/B&E (with no intent to commit a crime), and minor property damage. Jon would, at most, get probation and some fines that his father would have no problem paying. And that's if Jon got convicted, which is very unlikely, considering - as Arthur told him - what jury is going to convict a guy who went to find a dead body that his "friend" confessed to hiding and then saved that girl's life? And not just any girl, but a very prominent missing person. Either way, it would be a huge waste of time and money and not make the Lannister-Baratheons look any better