I've brought three trucks back from the edge.. all three hadn't been run in at least 20 years. All three were pre-53 (one was a Dodge) and all three needed to have that foot stomp switch cleaned out before they'd do anything.

If your local autoparts store stocks that top of the starter mounted switch, replacing it would probably be the best bed, but i'd test the starter motor itself with the switch removed using the method I mentioned above first thing.. that will tell you quick if your starter has given up the ghost.

In my experience the battery terminals don't have to really be tightened down.. I regularly play musical battery between the three trucks and my Farmall M.. I just pop the terminals on by hand and turn them till they snug a bit and off I go.. but you wanna make sure your cables are good.

Just because both ends look good or are clean dosent mean there isn't some corrosive funk living somewhere in the cable.

an idea is only stupid if you think about it rationally.