RE: the oil issue, it sounds like you’re seeping oil past the threads of that sending unit. This should be a quick fix for an affordable price. The switch is cheap http://www.car-stuff.com/store/?N=11626+4294963744+1558+11921+5994 and it installs really easy.
Perhaps also some is seeping past the valvecover gaskets, and it’s dripping onto the exhaust manifold or header pipe. A stuck PCV valve can exascerbate this, but the valvecover gasket may just have lost its compression due to age…and having been long conpressed with oil seeping through. The basic and root cause is probably lust engine wear, blowby, the combustion gasses blowing past worn rings and pressurizing the crankcase (with is connected via the drain passages to the space under the valvetrain).
I’d get that booster done BEFORE someone pulls uot in front of you…or some child runs out after a playground ball. Ultimately, one or the other WILL happen. And if you can’t stop, you and the child’s family will both have to live with the consequences. And don’t forget, there’ll be legal and financial consequences as well.