Water pump already done one good thing.
p.t.u couple of drain and fills and hope for the best with it.
200k on motor real risky.
This is like going to the casino you don't often win.
But for 2k maybe if it runs and drives well ????
naaa to many variables on the fills of 5w30 and the 10w30 again was only summer driven so the 10w probably didn't effect anything on the 75 degree plus cold starts . My thinking the 10w may be more shear stable under stress of high heat and load ??
In my 2015 I ran 0w20 5w20 5w30 and 10w30 .
Always a summer driven car so I never noticed a drop of any measurable amount in fuel milage and one of my highest recorded tanks was on 10w30 .
I found the engine seemed to run a bit more on the quiet side on the 5 and 10w30 and I never developed the...
So nobody here knows the car better than you do !
Do you feel it can make the 1800 miles safely and be relatively reliable while she is away ?
I feel your pain if it was my daughter I would be highly concerned as well.
For me the oil leak would not be a big concern take care of the vibration...