Navien30009757A Remote Controller

What cable can be used to extend the range? (I have about 20' to go)

Can you use the remote to turn the main unit on and off ? I want to avoid a trip to the attic when leaving on vacations .

Without batteries how do you charge the remote controller? Is there an electric wall charger?

How long of an extension can you run with the 18 gauge thermostat wire? I have the heating unit in the attic above the third floor and need 30 ft.