A word of caution... remember the distances we're talking about here...
Edwards AFB museum, if open, is a must.
Edwards (the USAF Flight Test Center) is well over 200 road miles from LAS. Not that it's a bad idea... What's more, Edwards is minutes away from Mojave where you can drop in and say hi to Mr. Rutan...
Either drive or fly to Chino airfield. About halfway between LAX and Las Vegas.
LAS to "Planes of Fame" at Chino is very close to 250 road miles. Chino to LAX is about 60 road miles. Although it may be "about halfway" in driving time
it is not halfway in road miles.
That having been said, the suggestions that have been made ARE excellent. Me, I'd gamble for a day then hit the road, even given these distances. Edwards is out in the middle of the Mojave Desert a billion miles from anywhere, but when you get there it seems as though you're at the center of the aviation universe. I've got lots of suggestions in that neighborhood for anybody who wants to wander out there. Like I said, Mojave is right down the road, and LA Center is also very close in Palmdale, but there are lots of other aviation-history sort of things out there as well, if you're willing to do some reading and driving.