You are right about the こと at the end of a verb. It turns the verb into a gerund, similar to the -ing in English.
“Running is hard” — ‘Running’ in this sentence is a gerund (a noun-ified verb)
はしる こと は むずかしい
What is the sentence “It’s boring for Tom to fly to America everyday” about? What’s the subject? In English, it’s a little tricky to say…technically the subject is ‘it’, but what is ‘it’ referring to? It’s referring to the act of flying to America everyday! So we can rewrite the sentence this way: “Flying to america everyday is boring for Tom.” So if we break that sentence into chunks, we can translate the chucks and then arrange them into a Japanese sentence order.
[Flying to America everyday] [is] [boring] [for Tom]
[毎日アメリカへ行くこと] [は] [つまらない] [for Tom]
The only part left untranslated above should show you that トムさんにとって has to mean “for Tom”.
A にとって B は Cです。 For A, B is C.