I have no idea when the resort might host a major national event, but I would say they would be wise to do some trial state level events before they jump in the deep end. In AZ we used to host the state senior four ball event and it sold out every year, the golfers seemed to have a very good time as they returned every year, and we did OK as a business as well. There are a lot of events like that looking for a home.
I would also suggest creating and hosting a major amateur event - probably at the mid am or senior am level. When you develop and organize your own event, you can do what you want, and for my money that often ends up a better event then having an outside agency come in and take over your property. Streamsong will soon have all it needs to host 250 players for a unique event. Do it in the shoulder season when the days are a little longer and you have inventory available and you'll attract northerners at the end or beginning of the golf season. From a business standpoint I'd probably try for a spring date at the beginning of the tournament season as you'd probably get some to come in early to shake off the rust. Don't pork 'em with some outrageous entry for the golf and you'll reap the rewards of butts in beds and F & B, not to mention all the positive press that comes with a well run event. If I was managing any destination resort that had good golf and lodging facilities, I'd be looking real hard at developing the tradition of a major golf event for good players. (preferably a partner event that finishes with match play - older guys know their limitations but still want to compete and have fun)