This is how I think the final book will play out (as far as Hermione's concerned.)
Hogwarts will, in fact, remain open.
Harry's original plan of not returning to Hogwarts will change, because he'll come to realize that while it's noble for him to begin searching now, the benefits of completing his training at Hogwarts will pay off when he's faced with Voldemort for the last time. (I must mention here, Dumbledore will still be around in the final book. All headmasters/headmistresses seem to have talking paintings, and Dumbledore did promise never to be completely gone until no one at Hogwarts was faithful to him).
In the time from the beginning of the book until Harry returns to Hogwarts, Harry, Ron, Hermione and possibly Ginny, Neville and/or Luna will be working on a plan to get rid of Voldemort once and for all. Harry's faithful friends (and I include Neville and Luna because they are definately faithful and now pretty sharp). In this time, the Ron/Hermione relationship will continue, but they'll be more friends than anything at least around Harry, so we'll never know much about their private time together.
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I believe Ginny and/or Hermione are in actual danger of being kidnapped or seriously injured, but not killed, by Voldemort or Death Eaters. I think that if it's Ginny, Harry will have more to do with her rescue. If it's Hermione, Ron will. Even if it's Luna, Neville will. All three of these girls are strong witches, and they're powerful enough to take out a few Death Eaters, and some very important guys care a LOT about them. Harming them makes sense from an evil mind standpoint.
After the rescue(s), the couples involved will be closer than ever, brought closer together by tragedy, but their love will be tainted by their scary, dangerous past.