I would have to say probably the best answer for you would be using WP robot if your going WordPress based. Granted the program does have a cost but if you are building a series of sites it would definitely pay for itself. Basically all you have to do for set up is create campaigns for auto blogging and hone down the article results with keywords. I don’t think it gets any easier in my experience.
I agree with Amish, auto blogging is a good way to get contents. But I think first you should get some guest bloggers who already have loyal readers, this will attract other traveler to write for your site. But everything that is free usually doesn’t come with good quality, including writing materials.
Although WP Robot may have some merits, their translate/rewrite section suggests plagiarism and that is something we will not be recommending in this forum. It would be ridiculous to spend money on a program and use it to publish content that results in you spending more money in a court of law.
This forum is dedicated to helping web owners learn how to acquire original content. Any further posts that suggest otherwise will be deleted and dealt with accordingly.
Have you tried opening your site for guest posts? You could ask your people there who are making content to moderate the posts, or something. I know you haven’t really made it that big yet, but that’s nothing that social media and some interactions with the other people in your industry can’t accomplish.
… It’s not a completely automated method, though. Even so, I do hope this can help.
User comments tend to work well eg: rate this bar/ restaurant/hotel (Spammers will be a problem but they are predictable and can be auto removed)
Events & gig calenders can be pooled from several sources. Some of the larger bars and hotel chains even have twitter and facebook feeds that could be grabbed server side