While I know this isn't exactly your idea, it's one I've had for a while and this seems like an appropriate time to share.

First, be specific. You may feel comfortable in the general "travel" space b/c it's bigger, but your message will just be diluted. Get specific -- I've seen discussions on HN discussing a site for travel that focuses on disabled accessible trips, etc. Hell, a trip that takes you to regional breweries might work here in California.

Anyhow, my niche idea is a museum system. People frequently attend museums when traveling, yet the museum makes you use their systems to hear the audio. Why not use the 2d barcode system to pull and TTS the wikipedia article for a given exhibit?

Applying it more generally, for your situation, and I would recommend that you focus your content on one niche.