[aerohead]

Your Toyota owner's manual will probably recommend upping your cold inflation pressure 3 psi for sustained high speed driving.Consumer Report suggest 3-5 psi over recommended pressure.Whatever you do,don't leave with them low on air! The extra weight and summer temps will conspire to heat 'em up,which could lead to failure.School is better than hospital any day! Try and distribute the weight as evenly as you can( like 3 passengers).Driving at a constant throttle setting(if safe in traffic) might be as good as P&G,as some mileage marathoners used this to win records.Remember,if your hyper-miling causes other drivers to waste fuel,we make no overall progress.