The additional information you posted doesn't make things sound too good to me, although I'm no expert. The oil on top of the valve cover gasket is puzzling, the only two things above it are the oil filler cap and the breather hose, both of which should be easy to tell if they're leaking. The puddle on the floor indicates something is leaking.

I don't know how many miles are on your car, or how much abuse it has suffered, but the symptoms to me sound like a worn engine with low compression.

The smoke after running the car sounds like oil leaking into the combustion chamber, perhaps through worn valve guides or valve stem seals. If you drive the car on the highway for a while and take your foot off the gas pedal, do you notice a plume of smoke in the mirror? Try it out. I had a 2002 in Germany that after running it at 85 to 90mph on the autobahn for a while would be like a mosquitto fogger when I let off the gas when approaching an exit. The closing or the throttle plate causes a vacuum in the rapidly turning engine (at least w/a manual trans)that is still turning at a high rate of speed since it is connected to the drive wheels. The vacuum will suck oil through the valve stem seals into the combustion chamber.

Also, if you remove the oil cap after the car is warm and is running and see a lot of smoke coming out of the filler hole, it probably indicates that there is alot of blow-by. This is exhaust gas that gets past between the piston rings and the cylinder wall. While some blow-by is normal, hence the breather tube routing gas back into the intake, too much is not a good sign. The engine will run rougher and may even stall when the cap is removed.

The overheating in traffic can also be a sign of a worn engine, as exhaust gases that are supposed to exit via the exhaust manifold instead are being circulated around inside the engine heating up the oil and coolant. At highway speeds the cooling system is better able to keep up with the demand.

The smell of gas could be an indicator that fuel is not being completely burned in the low compression worn engine. An engine with low compression is also hard to start, as the fuel/air mix is not being adequately compressed enough to be ignited by a spark. Once the engine is warm, things expand, temporarily increasing combustion making it easier to start when warm. The waiting for hours to start the car may be a matter of waiting for a flooded engine to vaporize the fuel.

The clicking noise your hearing can be any number of things to include injectors or valvetrain.

The best, least expensive things you can probably do are to, get a compression testing gauge, less than $50 at most any autoparts store and a Bentley book that will tell you how to use it. Only a few simple tools are needed. Zygmunt Motors currently has a sale on the Bentley book for like $40 including shipping. I noticed it after posting my first response. BUY THE BOOK! No, I don't get royalties (wish I did), it's just a really useful book.

Once again, I'm no expert just a long time DIY'er. I don't want to bum you out, the items I listed above are just possible answers to your problems. Good luck.

Thanks for taking the time to go into such detail. That definitely gives me several leads to go on. I am having the car looked at and I'll post the "results."

I'll definitely buy the Bently book right away!

Thanks again.
matt