Moving the car on and off of the carrier sometimes several times is something that simply can't be avoided.
Have you ever driven past an empty parking lot that had a car carrier unloading all of its cars? They do this frequently to shuffle cars around for which ones are being dropped off where. Those trucks drive all over the country to different places picking up and dropping off cars along the way. They pick one up, it blocks the two cars the have to deliver at the next stop. This is why almost all companies only want cars that run and drive, and will charge up to double the regular rate for a car that is not running.
I would agree with the making sure that it stays on the same truck. If the car needs to switch transports, they might even drive it to the other truck nearby if the two can't meet directly. I wouldn't be suprised if that's where your friends extra 30 miles came from.
My 442 was shipped from connecticut to minnesota when I bought it and wasn't damaged at all, and it was loaded and unloaded several times. The biggest thing is making sure your car isn't vulnerable to damage in any ways that could concieveably be avoided, i.e. car is really low, does exhaust hang low, etc...
It's been over seven years now since my car was shipped, and I hate to say that I have no recollection of what company it was that shipped my car, so I can't pass on a good endorsement...