Ok Robin.
I am not afraid to start from a begining, but I am not skilled enough to do it from myself. If You help to me in steps(as you post) I am ready to start with step by step.
If You remember my project before(wich is ready thaks to You) I learn a lot of things, but this is something else(other area with PWM, accel/decel, encoder etc.
Your simple sketch is the base. If I come on something with that I will post it.
First thing:
"Get the motor speed control working based on values in program variables (no user data entry)."
I dont understand exacly what do you mean with program variables?