You stole the car.... these are minor problems to fix compared to what it would take to earn the money for any newer car... which would never look as elegant as yours..
Your oil in the air cleaner is a busted diaphram on the vacuum pump..diesels have to make vacuum instead of just tapping to the engine's vacuum due to physics of the situation...
Approx 30 to 60 dollars plus labor... but you can do it.. following the instructions on this board.... plus you should be looking to find at least the Haynes manual for your car.
The factory shop manual says that the glowplugs continue to heat for up to a minute after you turn on the cycle ( assuming it is working ) .... so just leave it on 40 seconds after the light goes out typically.... to check to see if it just needs that extra glowplug heat to start better.
The fact that it started quickly and ran ok is a great sign overall. A good battery is only as strong as the connections to the cables.. put new cables and wire brush where they connect... remember how little you paid for the car and just go new on a few items like this... old battery wires can corrode INSIDE the rubber covering... so they can look good at the terminals and still be working against you.
There are several " tweaking" deals .... but you need the vacuum fixed and the valves set right from the start... sorry she did not do that on a regular basis... that should be your first priority just on principle....
With you in Montana and having stole the car maybe you should just put a new starter on there right up front... it WILL be getting colder ... I sure would if you need this car as primary transportation this winter...
Does it have a block heater ? If yes, be sure it is working if you have a place to plug it in. A block heater plugged in overnight makes all the difference in the world on starting a diesel in cold weather. If it does not have one put a good one in the standard place on the block.. OR find a generic aftermarket one and install per instructions on the package.... some need to be mounted vertically and low down on the engine relative to the coolant cavity to help movement by convection.. others pump themselves and are not as critical for placement.
After you get this other stuff replaced... check on your dash to see if you have an " unidentified button".... wait till you find correct instructions for adjusting it.... and your idle may be fine with just that tweaking ( plus the valve setting ).
As soon as you set your valves... run a can or two of Diesel Purge through the system... instructions are on the board and on the side of the can... it goes direct into the ip and the overflow goes into a jar... so you are using it full strength on the injectors and do not run it out of fluid in the jar... so as to not introduce air into the ip..
Good luck... let us know how things progress...