I use our GC to move pins two at a time all the time. 1/4 inch plywood 4*8 on the floor. First game in the back, rotate 90 degrees and slide up against the front seats. Second game straight in. No problem.
Side door opening isn't big enough to get a modern game in with the head on. Not sure about an EM.
Have to leave the front seats a hair forward to fit the plywood. Can do it without the wood, it's just much easier wth it.