Engine oil leak after the truck sits parked for four or more hours?

It leaks oil mostly after it sits with engine off for appx 4+ hours. i know it has a front intake leak, but it seems to be coolant. And oil pressure appears to be low it starts out at 40 PSI then drops to about 20 PSI don't know if it's the sender or really low pressure. Thinking about replacing intake gasket but if can't stop oil leak what's the point i read can't pull oil pan on these trucks without pulling the engine... don't know if I'm up for that. guess I'll clean the bottom of motor then trace out the leak hope it's not main seal or the pan you guys know what else to look for that may be leaking on these 2003 4.3s thanks again