Fuse is good; engine gets power since I can see it with a volt meter and the trim works. I can't see how it's a battery issue since the power to the trim is strong. I think it has to be in the control box somewhere or the ignition switch. I don't think its the starter solenoid since there is zero clicking or anything happening back at the moter when I turn the key. How can I jump the starter to make sure? Is there a way to test the ignition to see if turning the key opens a circuit? I still don't understand why the voltage gauge is not registering anything when I turn the key-- it clear that current is not getting to the gauge when the key is turned and maybe if it not going to the to the gauge then the ignition loop to the engine has a bad connection somewhere?
Check the negative ground connections as F_R suggests
The fact that you have power to the trim confirms that the fuse is Ok
Check for power getting to the ignition switch ( terminal B )
If not check the wiring between the fuse and the switch for breaks / bad connections .
If you have power to the switch suspect the switch .
It will help to refer to a wiring diagram. ( Impossible to do this sort of troubleshooting without IMO)
Not good because they are not in color but the one for the engine and the one for the remote in the manual on the Boatinfo site might be good enough
Be aware that digital volt meters take so little current that they can give a normal reading even through bad connections. I prefer to use a test lamp that will need some current to light up .