Resort openings are typically very low-key affairs. They'll have some sort of small ceremony (photo op) with an executive and Disney characters. I'm sure it will be covered by the Disney Parks Blog, along with other independent bloggers who choose to attend. In all likelihood, Disney won't even publicize the event in advance. Can always inquire at the front desk.
Did anyone attend the Saratoga Springs grand opening in 2004? Wow, that was a 3 day event! Really miss special revents like that.
If I'm thinking of the same event, it wasn't really part of the SSR opening. About 10 days after SSR formally opened, DVC hosted a "Member Homecoming" event which included a number of exclusive perks like a private night at the Magic Kingdom and some exclusive meals.
It was a paid event...and it was widely regarded as a failure. DVC didn't have nearly the presence at WDW back then as it does today. SSR only had its first 50 rooms available. AKV, BLT, VGF, Poly and Treehouses did not yet exist. DVC was literally about 1/3 of the size it is today--about 1200 rooms vs 3000+.
The Homecoming event wasn't publicized until 4-6 months beforehand. That lead to circumstances where members who wanted to attend couldn't get rooms and many members with rooms had no interest in attending.
They also had some mis-steps with event pricing. It was initially billed as including theme park admission, which served as a major turn-off for members with Annual Passes. DVC did later relent and offer lower event pricing for AP holders. Still, reports of sparse MK crowds and nonexistent wait times speak to the lack of interest from members. Nothing similar has ever been attempted again.