Iowans are packing up their picnics, suitcases and S-U-Vs and heading for the hills. The summer vacation season is in full swing and for those who can take Monday and Tuesday off, this is the first day of a five-day weekend. The experts say gasoline prices are -not- a big problem.Daron Van Helden, spokesman for Triple-A Motor Club of Iowa, predicts 36-point-six million Americans will be on the road this weekend. That’s up slightly from last year’s 36-point-three million travelers. Van Helden says most of them will be in four-wheeled vehicles.Here in the Midwest, Triple-A estimates six-point-two million of us will be out and about at least 50 miles from home this weekend. Van Helden says patience is the most important thing a person can pack on a long trip.Gasoline prices are averaging a dollar-40 a gallon in Iowa. That’s down almost 35-cents a gallon from both last month and one year ago.