I had mine one off not long ago, it wasn't difficult to get off and had never been off. I don't remember the size of the four bolts for the hub assembly, but they were not large--maybe 13 mm.
This is from the Chilton manual; it shows the hub assembly being unbolted after the brake drum has been removed:

Remove the four bolts retaining the axle hub, use this large hole in the hub to access them
- Before servicing the vehicle, refer to the precautions in the beginning of this section.
- Disconnect the negative battery cable. On vehicles equipped with an air bag, wait at least 90 seconds before proceeding.
- Raise and safely support the vehicle.
- Remove the wheel.
- Remove the brake drum or rotor.
- If equipped with ABS brakes, disconnect and remove the ABS wheel speed sensor.
- Remove the 4 bolts securing the hub to the knuckle and remove the hub.
- Remove the O-ring from the backing plate.
To install:- Install a new O-ring onto the backing plate. Coat the O-ring with multipurpose grease.
- Install the hub to the knuckle with the mounting bolts and tighten to 59 ft. lbs. (80 Nm).
- If equipped with ABS brakes, install the ABS wheel speed sensor.
- Install the brake drum or rotor.
- Install the wheel and lower the vehicle.
- Connect the negative battery cable.
- Have the wheel alignment checked.