The way I see it, why not?
I mean, basically, you are crazy, but it will be one interesting trip. It's something you can brag about. Even if your MB dies, you will have the journey. If you make it you will probably be very good at fixing MBs.
Just make sure to stock up well for your trip- keep your sidecar full of a few gallons of water, and fill up your bottles every time you stop somewhere with a faucet. Have extra gasoline and extra oil. Have clothing for all weather, space blanket, ect...
Keep an ATM card with some money on it in case you need to go to the hardware store (and have a wrench plus extra nuts, bolts, and washers/lockwashers), carry duct tape. Have a cell phone, but keep it turned off and only turn it on when you need to make a call. Oh, and road maps and atlesses. Do your homework beforehand and just make sure you take a route well populated- hardware stores, tractor/lawnmower dealerships, home depots/lowes, bicycle stores, ect.. are your friends.
And if the bike dosn't already have a gell seat- get one.
