I don't see what's not to get. He says he traveled there 17 times, implicitly mostly on business connections but in any case not as a political bigwig.
Then circumstances change. He runs without seriously expecting to win, but people apalled at the utter corruption in DC encourage him to take it seriously in the interest of the nation's good, so he does - and people respond, and he actually wins.
So suddenly he's gone from just another guy on a jet, somebody the swamp perceives as no threat at all, to the newly inaugurated president, walking next to a wife he loves, and he thinks the world suddenly has a lot of new promise to it.
Seems intelligible enough to me. But I'm only a native speaker of English for decades.