Rep. John Doolittle (R-Roseville) visited the Stonehouse Restaurant in Nevada City on Tuesday and expressed optimism about his campaign.The longtime incumbent is running in a hot race against Democratic challenger Charlie Brown of Roseville to represent District 4.At the luncheon hosted by the California Association of Business, Property and Resource Owners, Doolittle said he has been "very encouraged" by what he's seen on the campaign trail lately, adding that his bid for a ninth term in the U.S. House has been criticized by "carping leftists."Doolittle discussed war in Iraq, the economy and other topics at the banquet held at the …