Ensure ACT survives past November and is a viable coalition partner for National.
Take a ministerial portfolio in the next government.
Assume a more important portfolio as the Key charm begins to wear off in the second term, and as the tide begins to turn. Finance, for example.
Become Deputy PM.
Become PM by engaging in a full frontal assault on the PM’s credibility. The Brash style is, after all, to stab someone in the chest in a frenzied attack rather than slyly slip the knife between the shoulder blades.
Merge National and ACT and contest the following election on a platform of asset sales, deregulation and serfdom.
Win a majority and put plans into effect.
Engage members of the Climate Science Coalition and Birther movement to establish whether Articles 1 and 2 of the Treaty of Waitangi are a forgery. Conclude that they most certainly are.
While on a state visit to Australia, offer to become its PM. When offer is politely declined, launch another frenzied attack.
Next the US presidency. This will first require a constitutional amendment to allow a non-US born person to stand for office. Get that done by lunchtime, then run for office. This will be an outrageously expensive campaign, so time for the Exclusive Brethren to come good on their funding promises.
Once US President, start working towards one world government. Achieve this goal before 80th birthday. Send probes into space to seek out new worlds and new civilisations to conquer.
Put self into cryogenic state, with instructions only to be awoken on First Contact. Put Exclusive Brethren friends in charge in his absence.
Awaken to greet envoys from alien civilisation. Have them take him to their planet.
Launch frenzied attack upon alien ruler, seize their technologies, and go forth and conquer other planets. Explain that he is doing it for their own good, because their governments have grown too big and bloated, and the burden on the alien taxpayer is crippling.
Become absolute ruler of a vast network of planets and galaxies.
Die quietly in his bed surrounded by those he loves (stocks, bonds, gold bars, wads of cash).