You may want to get a breaker instead of a fuse so it can be reset. Fuses are fine to use also but buy several since you will be going through them until you find the problem.
The suggestion is to eliminate the starter solenoid from the wiring and see if it still blows the main fuse or not. Putting the test light in will still draw power through the wiring that activates the starter solenoid.
You have it correct.
Update: I made up a makeshift breaker from parts obtained at an auto parts store. Thanks for that recommendation as it worked without having to buy multiple slow burn fuses.
Per the process ctThomas outlined, I believe it worked. I unhooked the lead from the solenoid to the starter, and hooked the test light to that lead. I attached the breaker to the female end of the slow burn fuse connector. I then turned the ignition key to the position just short of start. The lights on the dash illuminated. I then proceeded to turn the key to the start position, the test meter light came on (was not as bright as full power but it did light up), and the breaker proceeded to get quite hot. So is it now safe to conclude that the starter solenoid is bad?
This has been a bit of a journey but Ive learned more about my tractors electrical system from his process and I am most grateful for the help provided in the posts. Thanks to everyone that contributed.