You want help. It needs to be lifted to take the pressure off of the fasteners that hold the tiller casting and rudder together. You don't need tools, just a helper. Support the rudder by pushing it fully up to the hull. Loosen and remove fasteners, then slowly lower.
To reinstall, simply reverse. It might take two of you to get the rudder re-stabbed, but once in the tube, a single person can hold it up, or it can be blocked while re-connecting the tiller.
There is a chance that on your trailer, depending on geography, that the rudder might not fully drop away from the boat. Start by dropping the trailer jack at the trailer tongue as low as possible, raising the transom. Failing that, you might find you need to dig a hole. My boat is on a pretty low-slung trailer sitting indoors on a flat floor shop, and the keel will drop with the trailer level so you should not have a problem unless you have the back of the boat parked up against a rise in the earth... Just be prepared to know you might need to address it...