LITTLE LEAGUE: Kent Grady, head coach of the AAA Minors Rangers, oversaw a delivery of 48 yards of 60/40 infield mix to the Nicasio baseball diamond on Tuesday. The field, which vandals tore up one night last year, is recieving $20,000 worth of upgrades, including fresh sod for the outfield. Mr. Grady hopes to get another $10,000 for things like a new mower and shed. The upgrades should start to save the field money within two years through water conservation and less yearly maintance and reseeding. The West Marin Little League and community donations are funding the improvements. Tax-deductible donations to the Nicasio Land Preserve can be sent to P.O. Box 532, Nicasio, CA 94946.