It really depends on how realistic you intend to be. Politics isn't always based on reality.

Realistically, we don't need to spend as much as we do on the military if our goal is to protect America's interests in the narrowest sense of the term. We could afford to safely close many of our military bases around the world. The realistic chances of America being attacked on home soil by a sovereign nation is close to zero. Regardless, cutting military spending is a very hard sell politically, one that approaches third rail status. That remains true even if you make a clear and powerful case that there are better ways to spend that money to protect national security (climate change, energy security, etc). American voters in general, and military-fed corporations in particular, want their security to come from guns and riot gear more than peace and prosperity for all. It would be an uphill battle to win hearts and minds on that one, but if political outsiders don't try it no one will.

Healthcare is an equally sticky situation. There are many reasons healthcare has become unaffordable, but among them are government distortions of the market. The lack of competition in big pharma (in part caused by a high regulatory barrier to entry for small pharma) coupled with government guarantees in the form of medicare and medicaid have led to huge profit margins for these companies. How much of a profit margin is required for viability is a subject of fierce debate but the answer is "probably not quite as much as exists today." But what can you do? Removing the government distortions means that many people won't get the care they need. Nationalizing the whole industry would probably end up being a regressive nightmare with low quality and low innovation. So how do you control costs? Obamacare seems like the best middle ground, which is why they did it.

The only alternative that I would really like to see tried is one where the government directly buys the patents for drugs that work well and produces and distributes them itself to control costs. This means that big pharma would only be in the R&D business and not in the manufacture and distribution and marketing business. That's sort of a middle ground between nationalization and the Xprize effect.

For taxes, the best proposal I've seen is a flat tax plus basic income. Basic income would be the progressive part and flat tax greatly simplifies the entire system. Rather than taxing the rich for a higher percentage of their income, you give the poor a much higher percentage of their income for free. Basic income is incredibly expensive, so the flat tax would probably have to be in the 30%-45% range, but you don't run the risk of triggering tax immigration or of being seen as unfair, which might become problems if you made only the rich pay for the huge cost of basic income. Such a system could have a similar break even point to the one we have today, and would be a much easier political sell than most basic income proposals.

In general though, if you want to get elected someday, it's best to not come on too strong. Focus on one core set of proposals and make them the easiest sell you possibly can. People are fed up with the current political parties, but first-past-the-post encourages everyone to marginalize all third parties. The realistic scenario in first-past-the-post for third parties isn't to win but to sway public opinion in a certain direction. I have a hard time imagining any futurist party candidate really winning anything outside of San Francisco or Vermont (though it never hurts to try). Even without winning elections, there are many ways to be an effective political advocate for these kinds of issues.