[jcims]

This seems to be nearly insurmountable if the primary objective of the site is only to meet people, particularly young single people that have no local social group or attachment.

One minor pivot that OP might consider is make the site about finding ways for travelers to integrate with the local community. Volunteering opportunities would be the primary idea that comes to mind, but if there's any mechanism to integrate with meetup that might be useful as well. Basically tie in systems that have already developed a survival mechanism to filter out creeps.