Tolstoy is difficult for beginners. But nobdy can forbid you try to read it :) It depends of your targets. I'm sure you can decide by yourself after couple of pages.

If Your Russian is not good it is probably not a good idea. Even for native speakers it is hard to read war and peace because of his too long descriptions of situation. You can read Chekhov's stories. He is also classical writer in Russia.

I have never read adapted books. I remember I made marks over new words and wrote words to my notebooks. If you have read War and Peace in your native language and if you like it, just search peaces your want to read in Russian, for example scene of Andrei Bolkonsky's declaration of love to Natasha Rostova or dialogues of Natasha and Pierre and so on, and work with these scenes. In language studies the most important thing is if it is interesting for you or not. If it is interesting for , you will not notice that is is difficult.

Tolstoy is famous for his paragraph-long sentences. that means that he uses a lot of participle phrases, parenthetical phrases, defining and non-defining clauses, etc. If you are not confident yet in these, I wouldn't recommend you to start Tolstoy. As Julia said, Chekhov, on the contrary, is famous fir his short stories.

Tolstoy may sound complicated even for native Russians. I sugges t you not read any classic literature as it would only complicate the language for you. Try to read something less sophisticated, maybe a book for kids? Or just a modern book where the ACTUAL language is presented rather than the one used a couple of centuries ago. Furthermore, you can just read the news on, let's say, slon.ru.