steve, thank you for your direct control suggestion.

My thought is to hack into the present connection between the RC receiver and the ESC for the drive wheels. I figured with a DPDT switch I could toggle the two wires that are presently connecting the receiver to the ESC (the third wire is ground) between their present state and the PIC. Two wires, one DPDT switch. The red wire is PWM signal. The white one is Vcc. (Actually I think I should leave the white wire floating. Let the ESC use its own power to interpret the PWM signal.) Good idea? No? Insert a diode?

The RC receiver gets its Vcc and gnd from the ESC. My ancient Triplett multimeter tells me that this Vcc is +5v. I know the battery is +7.2v. The ESC must have a 5v regulator on board.

The other DPDT switch is needed to perform much the same operation on the Vcc and signal wires between the receiver and the steering servo motor. In this case the white Vcc wire is driving from the receiver. This one I will switch and drive from the PIC when it is in control.

Thus when the PIC is in control the RC receiver's 5v comes from the
PIC. When the third RC channel signal commands return to RC control the PIC will interpret that and flip the DPDT switches back.

I have this on paper drawn by a #2 pencil. Unreadable by anyone but myself. I'll make you guys a schematic. That may take a couple days. I will be distracted tomorrow and I need to learn about CAPTURE ( I have a bootleg copy. I have to give it a try.)

Ken