Remember, standard Republican playbook is "government is
  bad", so the base doesn't really mind seeing the EPA things
  gutted.

That's a critical point. If your narrative is that government is intrinsically broken, then you already have an excuse for when you fail at governing.

The GOP has turned into a permanent opposition party, incapable of governing. IMO, anybody who earnestly casts a vote should vote for a Democrat, or some candidate willing to caucus with Democrats. Even if you're a classic small government, low taxes kind of person. Even if you're libertarian. Even if you're a conservative culture warrior.

Americans who vote for the GOP are like Venezuelans who vote for the United Socialist Party (of Maduro and Chavez). Both parties have crafted a political narrative that effectively immunizes them from criticism, even as they sink the country into political chaos. Anything they do wrong can be blamed on the opposing side, and the base largely accepts it, or at least acquiesces. Things won't turn around until the leftists in Venezuela hold their noses and vote for the capitalist "elite". Likewise, things won't turn around in the U.S. until those on the right hold their noses and vote for the leftist "elite". And in both cases they need to do so for as long as it takes for the broken party to re-internalize notions of compromise and power sharing.

People need to put their ideology on the back burner for a few election cycles and focus on rebuilding civic society. If you agree with that then I think your choice in the next election is an easy one. Don't listen to the rhetoric or campaign promises: focus on the past 30 years of legislative outcomes and political strategy. One major American party more than any other has systematically worked toward destroying, both rhetorically and in actuality, efficient governance and the legitimacy of political compromise. To do so they've had to attack the fundamental legitimacy of science, but science is just one of many victims along their path to power.