So. Calif: I-15 at Cajon Pass and also at Las Vegas

Check traffic on Google maps Saturday morning for the three Saturdays before your trip. I am inclined to say you are better to take 215.

https://www.google.com/maps/@34.1543645,-117.4415723,11z/data=!5m1!1e1

Sunday morning going North through LV should be easy. Again check traffic but I think you can sleep to 6a (or more) if you like. I use the left 'through' lanes if just passing through.

https://www.google.com/maps/@36.0911257,-115.0959628,11z/data=!5m1!1e1