Just follow the story and join Railroad and then the Synth without advancing further into their questlines. Then accept the Brotherhood and enjoy how Paladin Dance comment your skill though the synths aren't attacking your character except in the building reception. After also joining the Brotherhood and without advancing their quests, your character has the best opportunity to explore the whole wasteland with the support of both settlers, railroad, synth and brotherhood, so either they'll kill eacother leaving stuff top scavenge or they'll support in many places towards mutants, ghouls, etc etc..

Edit: Also while wandering the wasteland clearing out settlements without actually settling any yet, that makes it just easier than trying to catch settlement emergency calls in the middle of exploring. It fits story-wise because the character found out about the institute and is now exploring the rest of the post-apocalyptic situation before continuing the saga.