I have a lot of white oily smelling smoke come from the exhaust when I start it after driving over 30 miles at one time. Doesn't do it if I just drive around town. Held a cloth over exhaust and no residue coming out of tailpipes.

if it was just on start up the water is condensation that has gathered in exhaust from sitting the oily black is condensation mixing with the carbon and residue in exhaust system this is a normal condition -------but if the vehicle emits a steady flume of white smoke or steam all day when driving then will need to check for possible head gasket problem

White SWEET smelling smoke, or white OILY smelling smoke? If it's white thick SWEET smelling smoke, you have a blown head gasket - that's the smell of antifreeze burning in the engine, which it should NEVER do. If it's white OILY smelling smoke (smells a lot like diesel), then you're getting too much fuel into the cylinders.

If it's sweet-smelling smoke (antifreeze), pull the oil dipstick & check the oil level. If the oil level is HIGH and the oil looks like a mocha milkshake, that's absolutely conclusive - that's what happens when antifreeze gets into your oil, and it's nasty corrosive to engine parts.

I'm not at all surprised that the oil light is on if it won't start - you won't get much oil pressure until the engine is running.

You may notice when fired up blue smoke that fades when warm, oilrings worn..

Yes

blue is oil
White is coolant/water It will also smell kind of sweet
black is fuel

If you don't drive your car very many miles or let it sit for days/weeks at a time it is most likely condensation in the exhaust. Take her on a nice 50 mile brisk drive and see if the problem clears up. If it does think condensation if not you will need to dig further.

Valve seal leaks will cause an engine to smoke on start until the oil burns off. If a head gasket were leaking it would be smoking constantly.

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Not to worry. Run the engine up to operating temp before jumping to conclusions and let the heat burn off any excess oil. A leaf will not do any damage.Do not let the engine overheat while idling and if the oil light comes on switch off immediately.
The smoke from the exhaust is oil deposited by oily assembly hands just burning off. It should dissipate after about 15 minutes at most.(or 5 miles' drive)

White smoke on startup could be a head gasket leak between the water jacket and the cylinder. Won't always show in the oil. Antifreeze makes it smell oily or sweet. Compression test will tell for sure. Bluish is oil that was burned. White is usually water or oil into exhaust after combustion.

White smoke is caused by coolant or water coming out the tail pipe. There is a chance that the white smoke was caused by water splashing up from a puddle onto the exhaust pipe. Keep an eye on the coolant level in the radiator in any event. If its less then there leak coolant leak in the car engine which is causing this problem....