Yes, to maximize your points/status qualification for a long stay like that you absolutely need to break up the stay into multiple different stays at different properties. Hotel hopping is your friend!
A little early to know what all promotions will be going on across all chains in the Aug/Sep timefreame but once they are announced you can then plan your hotel hopping accordingly.
I hardly ever stay at Marriotts since my impression is that anything other than their absolute highest tier gets zero in the way of benefits and they were unwilling to consider a status match at all.
In that area I've stayed at the Hilton Parsippany and found it a decent enough place. Nothing special but certainly adequate.
But yeah with 60-90 days you could rack up quite a lot of points and make a big dent in status qualifications with 2 or 3 programs if you are willing to hotel hop liberally.