Don't expect a Boeing 747 to fly into the old Nevada City airport any time soon - landing gear hasn't touched the strip in decades, and many newer residents don't know it exists.But what was once a sub-par tarmac for small airplanes could soon be a state-of-the-art solar farm to raise revenue for Nevada City. The proposal also is drawing new attention to the wooded areas just northwest of downtown including the Cement Hill and Hirschman's Pond areas.Neighbors are anxious for the city to snap up an adjoining, federally-owned property that, according to local lore, includes the site of the …