"Russia is far."
It looks like the country is Россия and "Russian" as an adjective (though probably genitive or something?) is ру́сский.
It’s indeed an adjective. The adjective originally comes from the word Русь 'Ruthenia'.
The adjective «росси́йский» means 'related to the modern country of Russia', while «ру́сский» means 'related to the Slavic people mostly living in Russia'. Russia is a big state, not only Russians live there but also Tatars, Bashkirs, Komi, Buryats, Kalmyks, Yakuts, Chuvashs and many other people live there.
See this discussion for more information: https://www.duolingo.com/comment/11651303
Sorry, what's your question? :?
No, you're confusing two different words. In Russian you have Русский and you have Россия, the latter of which refers to the country (which is what we want in this question). I hope that clears it up for you :)
Yes. Compare with «Росси́я зде́сь» 'Russia is here'.
You could use an adjective here: «Росси́я далёкая» or «Росси́я далека́» (short for of the adjective).
«Далеко» is an adverb, «далека» is a short form of the adjective. Both work here. Long form, «Россия далёкая», might work too.