What all do I need to purchase for towing a U-Haul trailer (the larger one)?

I already have the hitch/receiver which came with the car.

I'm hearing I need a 14" or so receiver extender to clear the spare wheel/tire.

I know I'll need a ball. Should I buy a ball guard?

What about the drop down dimensions for the ball mount? Do I need the ball to hang lower for the H3 with a U-Haul trailer? Should I buy one with cushions?

Can anyone recommend a good online store?

Sorry for the stupid questions... I really prefer not to tow at all with my new H3 Alpha ... but I guess that's what a truck is for and my daughter moves out in a few weeks. I don't mind spending a little more to buy good stuff as my boys move home from college next year.

Feel free to PM me. Thanks.