Either for speed or range, it is important to consider aerodynamics ... and road load.
I found some nice charts-graphs that really help!

Basic aerodynamic shapes - w/drag coefficients

Human Powered Vehicle Performance

Drag , via bicycle type - 22mph

Most impressive, to me, was that the "Upright Commuting Bike" requires almost exactly 2x the energy to maintain 22mph, as the "Racing Bike, Rider Crouched"!
("Air Drag", "Rolling Resistance" combined)

Watts required to maintain various speeds
(Note: These, tested, eMotorcycles are equipped with full front fairings!)

Pedal assist capability, Average & Athlete