If you decide to go down the IHG route and want to maximize your points, look into the Chase IHG credit card. The fee is only $49, which is more than offset by the free night you get every year. Many other benefits including 5X your spend when you use the card at an IHG hotel. You also get instant Platinum status, which earns you a 50% on the base points from every stay, and a 10% rebate of your points when booking a free night.

Right now they have a 60,000 point signup bonus with only a $1,000 spend in the first three months. https://creditcards.chase.com/a1/ihg...footnoteModal1 With your amount of travel that should be very easy to achieve.

And be sure to register for the IHG quarterly promotions, which can easily earn you tens of thousands of points and occasionally free nights as well.

Good luck!