MK offers the "co-pilot" which is based on the magnetic bearings/headings on a compass and is controlled by a remote. The co-pilot will keep the boat going in a straight line. Just google the MK co-pilot and should find lots of info on it.
You should be able to find a good used one on CL or other FS listings, people are always upgrading. You might even find a good used TM/co-pilot combo on CL as well or other fishing forums.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.