Boxes to check when home-buying: safe streets, good floor plan, strong school district and … a promise to be nice? At Silverwood, a new large-scale development in the High Desert city of Hesperia, California, buyers must sign a kindness pledge to their neighbors-to-be . The 9,000-acre project –– where starter homes can go for just north of $400,000 –– has sold 225 units to date, with some 15,000 more in the offing long term. The big draw? The price, of course, and the recreation of nearby