I'm a 25 yr old Austrian female who graduated university in Vienna in '08. I have a friend in NY and we hoped to travel extensively in the USA. I came to the USA on a 90-day Visa waiver 3/08; stayed through 5/08; and returned 7/31/08 on a 6-month B2 Tourist Visa that ended 1/30/09. April 9 my I-539 Application to Extend (for 6 months more) was denied. I've lost my B2 status and must leave by 5/9. We still have travel plans and I want to return as soon as possible on another Visa waiver.

1) What would be a safe time period to wait to avoid rejection? 1 month? 2 months? 3 months? Longer? I wanted the summer here.
2) Is it a surer bet to try to enter by land (from Montreal) vs. flying into NYC's JFK?
3) If I jointly-owned property in the USA would it be easier when I want to come?