Sell it and buy a new one in MD. It ll be easier and it may be cheaper in the long run.
What Marvin said - Craigslist is your friend.If you really really love the bed and can t part with it, then consider trading one of your cars for a van.I ve moved a lot too. The cheapest way I know to get a small amount of furniture moved is to use one of those moving pods. Even one of those, from the left side to right side of the country will cost over $500.
What about renting a uhaul, that would probably be the cheapest way then paying a company to bring it out to you. If all else fails you could just try to sell the bed and buy a new one whenever you get out to MD. It would probably be cheaper then spending a 1000 dollars to get it moved.
When I moved halfway across country with most of my stuff, the moving company put the rest of my stuff on a truck with other people s things. It was a lot cheaper that way. But for just a mattress, I agree with sell it on CL or in the paper, and get a new one in MD.