Adding a Trolling Motor

I had a rough time trying to leave the lake via the busy dock at Folsom Lake in Northern CA. I would like to get a motor to help with safely getting to and away from the dock in my'94 C14.2.
Few motor questions:

• How much thrust?
• Which size/kind of battery?
• Are the motor and battery OK in a capsize?
• When trolling, do you need to raise the rudder?

In the meantime, at the lake, if the wind and traffic are not optimal, should we just row to the dock?