Recent 300cd turbo purchase

[patc]

Well I finally have my first MB. Its a 1983 300cd turbo. It is basically in fairly good condition from a body standpoint. I found that the return lines are leaking and have been told that this is a DIY project. There are several lights out, the radio and power antennae do not work and the sun/moon roof moves about an inch before I can here what sounds like some gears slipping in the roof, and its slooow as all get out(turbo what?)The milage is around 185K. Other than belts, hoses, etc. what should I have checked out to assure reasonable dependability. How can I check the overall health of the engine. I'm an electrician and am not afraid to get my hands dirty on DIY projects but I realize that there are some jobs better left up to the pros. What would be a good reference manual to get my hands on? This site looks like an invaluable tool~!!!!!!!
Thanks in advance!!!!!!!!!!!!!!!