AP Previews run during normal operating hours of the park, the entire time, unless there is a techinal difficulty. Sometimes, if the park is open really, really late during an AP preview, they may close an hour or two early, Otherwise, it is during normal park hours.
During AP/DVC Previews, ONLY those with an AP, PAP, or SP (annual pass, premium annual pass, or seasonal pass) are allowed in. People with Magic your way plus tickets are not allowed in, contrary to what people think. Your WDW Resort key is not acceptable for admission to the preview either. Sorry to sound rude, but just stating the facts.
So, unless you have a VALID AP, or a DVC Membership Card (also has to be valid), you will not be able to experance the attraction under preview.
Sorry, I know that's not the news you want to hear, but just the way it works.
The preview for Soarin' is April 15, 16, and 17. (a Friday, Saturday, and Sunday)
As with Philharmagic ONLY passholders will be allowed to ride, even though Soarin' has had a soft opening before the preview. Mission:Space had soft openings before the preview as well, but during the dates, it was open for passholders only.
If you have any questions just post...I'll try my best to answer them.