I have hit what I think is the first branch point in the main quest where I can A.Help Mr House upgrade his robots B.Kill Mr House and help Yes Man take over (and upgrade the robots) or C.Kill Mr House and then help the NCR/Legion/whoever rather than helping Yes Man.

Does anyone have any tips that might help me decide which way to go? Or should I leave this alone, exit the casino and go off doing side quests for a while before I decide which way to go on this branch?

I want to be a "good" player and not do anything evil or bad for humanity or bad for my karma and am generally trying to be a macho strongman character. I have the Steam collection edition with all the DLC.

Not asking for someone else to make the decision for me since I know its one I must make, just asking for advice on what the different choices mean to my goal to be a "good" player (with good karma) and to be friendly with as many factions in the wasteland as possible. (I happen to like being friends with the NCR and the Legion and dont like the thought of having to kill too many of those nasty looking things with guns for arms, a TV for a face and a wheel for legs, whatever they are called)

This is the first RPG I have ever played that has a distinct branch in its quest line, all the others (Oblivion, Fallout 3, Diablo II and others) have been fairly linear so I am not used to this idea of branches in quests

I would advise playing for the House on an initial run of New Vegas, but...

Yes Man is a decent adviser on who to know.

I often attempt to stay at Accepted by every Faction but Powdergangers until committing to a Story Arch. Aiding the Legion and the NCR can be done by doing Quests that do not hurt the Opposing Faction. Do smaller Quests for Faction Members, and get Idolized by Goodsprings and Novac if still possible. Work for "Neutral" Factions around New Vegas like The Followers of the Apocolypse.

I do not deal with ending House until after becoming Idolized by the Boomers, usually.

Talk to the named Legion at the Fort, some of Thier Quests can be done without aggravating the NCR or an Indy/House playthrough.

What will be a struggle to decide is what is the "good" option for the Mojave? As above, wander around, talk to people and complete side quests, and get to know the land and its people.

This. Don`t rush into the main quest too quickly as the game ends when it`s concluded. If you`re having trouble deciding which path to take, it`s a good opportunity to go off and do some other things instead for awhile until you figure it out. Ultimately though it`s only your decision as to which side to support. There are four distinct paths to follow to reach the end of the game, and you need to decide which one to take. Personally I find the path that is the most good to be Yes Man.