I've been rear ended once in my truck, and it was fine. I was ok, as was my mom. The lap belt gave me bruise across my waist and I had an arched bruise from the steering wheel on my chest, but those went away. I feel safer in my '66 than in my '91 Honda Accord, the truck has substantially more metal in it.
For the brakes locking up, thats a common problem. I would check and see how tight you have the brakes adjusted. Jack up one wheel at a time, and spin that wheel and you should feel some resistance, and it should slow down gradually. If you really do stand on the pedal (emergency braking) the wheels will lock up. It does take some getting used to stopping with manual brakes.
