Welcome to the forum @mikep! What kind of truck are you driving right now? a F-150? I'll try to help answer your questions as best I can. Hope this helps.
So as far as the Tesla adapter is concerned this is what you'd be looking to get. Like you said it's good on Tesla chargers that are not Superchargers.
ev-lectron.com
The difference between kWh, volts, and amps is that kWh is used to describe how big an EV's battery is and volts and amps are used to describe much electric charge can be delivered to an EV.
Here's a good video that explains charging tips for the Mustang Mach-E that should give you an idea of what you can expect.
insideevs.com
So as far as the Tesla adapter is concerned this is what you'd be looking to get. Like you said it's good on Tesla chargers that are not Superchargers.

Lectron Tesla to J1772 Adapter, Max 40A & 250V - Compatible with Tesla High Powered Connector, Destination Charger, and Mobile Connector Only (White) [For J1772 EVs Only]
Lectron Tesla to J1772 Charging Adapter 40A. Compatible with Tesla High Power Wall Connector, Destination Charger, and Mobile Connector.

The difference between kWh, volts, and amps is that kWh is used to describe how big an EV's battery is and volts and amps are used to describe much electric charge can be delivered to an EV.
Here's a good video that explains charging tips for the Mustang Mach-E that should give you an idea of what you can expect.

Ford Mustang Mach-E Home Charging Tips
We offer an overview of how to charge the Ford Mustang Mach-E at home including how long it takes and what equipment you can use.
