As brevity is the soul of wit, Simplicity is the soul of engineering -CC
The "best drivetrain" is always the next one

Wide/Narrow front single chain ring
correct chainline
Cassette hub for strength with a 8spd cassette
Know your rear mech limits when choosing cassettes
Low gear as needed for the big hill
#4 sprocket gear should produce your cruising speed
You can always coast if you run out of gear at the top.
Enjoy lighter, simpler, cycling zen -CC