Anytime we ask ourselves what Oswald was thinking at any given time, we are speculating because he was the only one who knew and he took those secrets to his grave. If you believe in a hereafter and you go to the hot place, maybe you can ask him.
Obviously his decision to kill JFK was not done on the spur of the moment. That took planning and preparation. He made the bag for concealing the gun on Thursday at the latest. His traveling to Irving on a Thursday rather than his normal weekend trip is an indication he went there to fetch his rifle.
His actions post assassination are another matter. We have no idea what he was thinking from that point on. He probably knew he would be the subject of a manhunt and his decision to get his gun might well have been to arm himself against a cop(s). The fact he killed the first cop who encountered him and tried to kill the second is a strong indication he didn't intend to be taken alive. The cops would have been legally justified in killing him in the theater but chose instead to act with restraint.
At least in my view, any explanation - LN or CT - is more plausible if one can articulate a rationale that at least makes sense. As I've stated repeatedly, this is the problem with most CT theories - they simply do not make real-world sense; quite the opposite in fact. Many LNers, on the other hand, posit an Oswald who was almost a madman - something that I believe to be far from true. Or alternatively a madman and an inexplicable riddle (e.g., at Irving the night before). Or alternatively they take the position that "It doesn't matter why he did it or what he was thinking - HE DID IT!" Well ...
"He made the bag for concealing the gun on Thursday at the latest." This is pure speculation. There is evidence that what Oswald was carrying on the morning of the 22nd was not the bag found in the TSBD at all. This is surely one of the weakest links in the LN narrative.
"His traveling to Irving on a Thursday rather than his normal weekend trip is an indication he went there to fetch his rifle." But then you bump up against the behavior that suggests something quite different.
If I thought it was all as cut-and-dried as hardcore LNers make it, I'd have a hard time explaining to myself why I was wasting time at a forum such as this. Perhaps the LN narrative is some folks' version of a fundamentalist religion, and anyone who dares to raise questions is an infidel?