We have a geriatric Golden Retriever and a three legged Lab/Chessie cross. Since neither one of them is a jumper any more, we use two fairly short x-pens hooked together. They have plenty of room to move around, but they don't get the run of the site. The pens are the very first thing we unload when we arrive. The dogs go into the pen before we even unhook the trailer, so we don't have them in the back seat of the pickup bouncing around and anxious.
If you use a tie out cable or chain, just make sure to tie it somewhere other than onto the table. Having a pup jump onto the table is trouble waiting to happen. They just have a tendency to keep going and will jump off the wrong side.