That's how I roll too. I use the keyboard to maneuver and when I am facing my target and it comes to actually aiming I switch to the mouse. It takes some getting used to, because if the target goes off screen you're back on the keyboard, but it beats striking the mouse against the desk like flint on stone trying to start a fire.
There is a script or something that exists that makes your mouse behave like a joystick or something. With a calibrated centerpoint and any deviation of the mouse from that centerpoint moves the ship continuously in the direction away from the centerpoint. I haven't tried it personally myself.