Mega Miles states "On your 2nd stay earn triple miles".
Does this mean your 2nd stay at THAT property or your 2nd stay at ANY Marriott property during the earning period of 1 Feb to 1 April?
i.e. I stay at a Mariott hotel in DC. 1 week later I stay at that SAME hotel. This stay I get triple miles right? But if say 5 weeks later I stay at a different Marriott hotel will I get triple miles for that stay also?
Affirmative. Consecutive nights at the same property by definition are a 'stay'. If you check-in to the same property for a couple of nights for the duration of the promotional period, each 'stay' will count. Sounds like you already have an idea on where and when to spend those mega miles, so enjoy!