I'm happy for us Libertarians to work with Greens on issues where we agree. I'm happy for Greens to be better civil libertarians, I'm happy for Libertarians to more green, and I'm happy for both to promote electoral reform, ballot access, and decentralizing government.
But I'm against libertarian-leaning voters casting their vote in a way that announces they want less economic liberty or less personal liberty. So I think libertarian-leaning voters should only vote for a non-LP candidate if 1) their votes are likely to be the difference in electing the lesser of two evils, or 2) that non-LP candidate specifically runs on a set of positions that largely exclude the un-libertarian parts of her party's platform.
I've never heard of a GP candidate who would be willing to do that. As an LP candidate, I'd be willing to run a fusion LP-GP candidacy that focused on civil liberties, decentralism, and a Green Tax Shift. I'd be pleasantly surprised if the GP here (or anywhere) would want to get behind such a candidacy.
I'm all for blowing up the two-party duopoly. But I fear the GP enacting its current nanny-state platform the way the Socialist Party enacted its 1928 welfare-state platform: without ever electing a legislative majority or a president or even a governor. Similarly, I hope for the LP to enact (at least parts of) its current platform using the same strategy. So when legislators from the two incumbent nanny-state parties count votes for LP-endorsed GP candidates, I fear them counting those as votes for a bigger nanny state.
I'm skeptical that local GP+LP fusion candidacies can accomplish much in the absence of narrow short-term local policy goals, but I'd be happy to find out I'm wrong. GP+LP fusion won't send the right electoral signal unless there is a clear national-level statement of our common ground.
There are two good possible starting points for such a statement: 1) the Free Earth Manifesto, and 2) this redacted version of the Democratic Freedom Caucus platform. I would love for an intellectually-adventurous Green Party insider to take her red (or green) pen to either document and see how little she could cross out before finding the remainder supportable. I'm confident that the remainder would still be a bold and powerful statement for human liberty and ecological wisdom.
Update: another starting point would be the Ten Key Green-Libertarian Values.