vibration on highway between 65 to 70 mph.

HAve the tires balanced, next jack up each side of the car so the wheels are of the ground, grab the wheel top and bottom (12:00 and 6:00 o'clock) pull and feel for play hat would be a result of loose front wheel bearings, next pull the wheels in and out with your hands at 3:00 and 9:00 o'clock if you feel play now it would be more likely a worn tie rod end or steering rack inner tie rod link. Ensure the shock absorbers and other suspension components are free of excess wear. Spin the wheels see that they spin freely and have no excess run out (bent rim) or "hop" up and down (defective or out of true tire, on race cars and old cars people used to "true" the tires with a tire trueing machine long lost art. Tires are made to better tolerances now.