I don't know what the regulations are for an ebike. Normally you need to wait until they open the gate to enter, but bikes or foot traffic can enter early and avoid the need to arrive an hour or more before sunrise to get in line.
In general, the best strategy is to park and walk along Sparks Lane or Hyatt Lane. Bears will look a little ragged due in the spring, but you might see some cubs and the mother on dead logs hunting for grubs. Bears can be found anywhere in Cades Cove, and they quickly attract a crowd. Anticipate where the bears will go when people get too close, and move in anticipation of that movement.
Cades Cove is a one way loop. If crowds are heavy, work back and forth on Sparks and Hyatt. Avoid the visitor's center and mill area at the west end beyond Hyatt Lane if it's crowded.
With a big camera you are the target for rangers if you get too close. Set a good example.