I'm doing a branching style. I.e. pushing each faction's quest line as far as it goes before becoming an enemy of anyone else. I was level 39 before I started making enemies.
I did the BOS quest line first because I couldn't continue with either the Institute or Railroad without angering them. Finished that at level 42.
Currently on Institute route, which I've found I could push further before angering Railroad. Currently level 41 and just doing the side quests for now.
Plan would be to diverge to the Railroad after I finish the Institute route, before finishing with the Minuteman. This way, I can try to be of the highest level possible when I finish each of the faction quest lines.
If this is anything like Bethesda's previous games, 2837645509678476658373 playthroughs is my plan.
Actually planning for 5 runs. The game has 8 endings, one of them really stupid, not a real ending IMO so not going for it.
I have quite a few interesting roleplay hooks and character motivations planned.
Beth needs to fix their gamebreaking bugs and UI flaws first though.
I'm all set with one. I have other hobbies besides games.
I don't have any set number of playthroughs in mind. Considering I still do playthroughs of pretty much every Bethesda game at least two or three times every year (sometimes more, as is the case with Fallout 3 and Skyrim lately), and considering the fact that I've barely scratched the surface of the Commonwealth (not including DLC whenever they come out), I can see myself doing easily 30+ playthroughs within the next few years.