I agree that hills is a problem, but all it requires is training. Many years ago I lived in Sundsvall with many steep hills, I learned to take pretty steep (but not very long) ones at speeds up to 27 km/h, but of course it was exhausting. My average after a couple of years of triking was around 27 km/h on 50 km courses, that partly was pretty hilly, and I managed an average of 31 km/h on 10 km course with average climb of 1 procent.
My speed record was 76 km/h, and it was on a long descend on a typical swedish gravelroad, that has got a pretty hard surface along the tracks from the car wheels.
The trike was an old, narrow and low pre-production Steintrike. You really learned to lean in order not to lift the inner wheel in turns, which is pretty easy to learn. Hence I like narrow trikes. The Steintrike had a track of 64 cm and that is a kind of maximum for me on an open trike (whithout bodywork).
/Bruno