Getting the dart ready for its first road trip?

The plan is to drive my dart down to the Holley hot rod reunion in a few weeks. The farthest I have driven the car lately is about 20 miles though and I am a bit nervous about the journey. I have two main concerns. The first is the trans which is shifting through the gears before I get over 30 miles an hour. I have a thread going on that.

My second issue is I am getting absolutely horrible mileage out of my .30 over 360. I'm running an edlebrock 650 avs and have 3:55 gears behind a 727. During my 20 mile trip I was getting about 10 miles per gallon while cruising at 65 mph at 3200 rpm. The mileage seems very poor to me.

Other than that I'm prepared. I have a spare ignition and wires and coil with a good tool set tool set in the trunk.