coolant leak, backside engine, 82 PU

I have an 82 caddy with a 1.7 CIS. I find much oil leaking out onto the backside of the motor that I see below the intake and exhaust manifolds. I figure that it must be the valve cover gasket leaking. What bothers me is that I see coolant on the backside of the motor as well. The only place that it can be leaking from is the head gasket right? I also drive my truck strickly on short trips during the weekdays and I found a bunch of whitish sludge in the oil and on oil cap at the end of a cold week. That is condensation in the crankcase right?, or is that a leaking headgasket. I got 150K on the truck. Need advice ASAP. Thanks.