The older 3 speed hubs , both Strumy Archer and Shimano had a good low for flat ground and a big jump to second not really adequate for unassisted pedaling, then a similar big jump to the high which unassisted was a pretty high but not as high as your cassett would offer. The gears would be good for except for the smallness of the prawls inside that might be too fragile for the motor torque.
There are some newer 5, 7 and 8 speed internal gear hubs that would probably be stronger choices. The Rohloff 14 SpeedHub
internal I understand is just about indestructible but very expensive.
LennyHarp of Lenny's Bikes & Things
The true value of a man is not judged by what he has, but rather by what he can do without.
"We are what we repeatedly do. Excellence, then, is not an action, but a habit." -- Aristotle