Simply don't. It makes you look cheap, and can have the exact opposite effect desired.

Look at this website. Yamagata Prefecture, where I live, has declared that they would like to increase the number of overseas tourists, but somehow they think using a machine-translated site is going to do that. What that means is, they are not in the slightest bit serious about it. If they were, they would put money into creating content that their target market wants, stories from the prefecture that resonate with people and make them want to visit.

What we have now, is an atrocity. With an efficient site, like the Wakayama one, with well-researched keywords and attractive photos, they would be able to target people who search for experiences in Japan, rather than people who search specifically 'Yamagata prefecture'. Right now, if you do that search, the prefectural page isn't the first one to come up, although it is arguably filled with the most information, and it's simply unreadable. Anyone who came across it would think that they aren't really welcome. The prefecture can say they want overseas tourists all they like, but until they implement a proper website, nothing's really going to happen.