Ebikes do indeed take the sting out of the hills, but they do not replace basic fitness and time spent in the saddle.  Battery management is key if you are looking to push your daily distances above that of your normal rides with consecutive days in the saddle adding to your fatigue, reducing the bikes daily range. 

1 Basic fitness from exercise once or twice per week. Can ride on flat or gently rolling terrain at a steady pace. Usually have the stamina to spend 2-4 hours out on a ride.  

2 Moderate fitness from two or three sessions of exercise each week. Can ride hilly terrain at a steady pace, or more demanding terrain but only for shorter rides.

3 Good fitness from regular exercise sessions and time spent actively involved in cycling. Can ride full days with sustained height gain, at a steady pace. Has experience with back to back cycling days.

4 Excellent fitness from regular training and a significant amount of time spent riding in mountainous terrain. Can ride in any terrain at a sustained pace on multiple back to back days.