In summary, the route was leave Goodsprings to it's problems, go via Hidden Valley and Neil's shack to Vegas, steal a bunch of stuff from the Silver Rush to finance entry to the Strip, talk to Yes Man, disable Mr. House, confront Benny so that he does a runner, head off to the Fort to fire up the securitron army. Then: meet up with all the factions (Boomers, Brotherhood, Great Khans etc) and tell Yes Man they are to be ignored. Let the assasination happen, then off to the Dam for the big showdown.
This was all on difficult, hardcoe and not using fast travel. I hardly went anywhere, and I would have gone to even less places only I decided to collect about 20 landmines so I'd have some chance of killing Lanius. That battle with Lanius was a total slog, had to re-loads of times because I was so under-developed. However I finished the game at the quite inexperienced level 10.
Some of you must have tried this. How low did you go? What do you think is the lowest level that would be possible?