In the first sentence, omit the second か and it'll be correct --> 日本か韓国に行きたい。
Concerning the second one, you can use と to count the things (nouns, or verbs + の) that you want, finish by adding で or の中で, and continue the sentence normally: --> 映画を見るのとレストランに行くの(では)、どちらがいいですか?