As a Brother dealer I'm probably not allowed to recommend turning it on its side.
But unofficially, I don't see it would be a problem. Make sure you lock the carriage in place, just slip a piece of cardboard down the side so the carriage can't move at all. Also just watch for ink draining out of the waste tube. Even if you take the waste cartridge out, there is going to be ink sitting in the tube.
If you are worried about the platten, its easy to unscrew.
When you are carrying the machine, just note the outer panels are NOT structural. Hold it by the edging around the base, all of the mechanics sits on a heavy steel frame in the base. Once you've moved it just make sure to clean out any ink that has spilled inside and do a cap clean.
And don't wear good pants that day.
Erik