New M-B owner. Just bought a 81' 300D

[PrestonEng]

I just committed to the purchase of 1981 300D. 127,000 miles on the odometer. This hasn't been started in 5 years, any help on getting this running would be greatly appreciated.
I have been researching this model on line since I found that this car was available a week or so ago.
Everything looks to be in fairly good condition. Some rust at the bottom of the rear doors, minimal at the jack points and low areas of the trunk. It rained earlier today and the rear floor is wet (sunroof or door seals?).
Rear axle boots and other rubber in the suspension and drive shaft look to be o.k.. The battery is dead so I couldn't do any electrical checks or try to turn the engine over(the crank is free,not frozen) . I did pump the primer a few times and it leaked fuel. Brake and power steering fluid looked fairly clean. Oil was at the notches on the dip stick (black of course).
I'm trying to get a charge on the battery before I go to get it with my trailer this Wednesday. It would sure be nice to drive it on as opposed to cable come-along and straps. Any suggestions?
Oh, I also hope that I haven't wasted my money on a big headache!