It's way easier to handle by beheading it - label all the connectors you take off, that's the era of williams where 2 of the connectors will mate but they shouldn't be connected, and it wasn't consistent black to black and natural to natural - sometimes they were cross connected.
The head is actually heavier than the body of the machine since the transformer's in the head - so it's harder to move the head because of the weight, the body is hard to move because of the bulk, but ultimately I find it easier to take the head off these games, especially if you're moving it in an SUV.
If you're putting it in a pickup truck, put the head with the BG facing the front of the bed with cardboard or a piece of plywood protecting the BG area, then bumper the back of the body right up against it. Run a ratchet strap on your tiedowns around the entire package and make it snug (put corner braces on the front of the cab if you're worried about damage).
Whatever you end up doing always secure the game to the bed of the truck.... you don't want it slamming around as you drive, and it will, especially if you have a slippery bedliner.
You might as well learn how to connect/disconnect the head now because at some point in the future, you're going to need to know how to do that anyway.
Oh, and take the ball out of the game so it doesn't fly around the playfield.