I'd prefer the ability to broaden the search radius personally. I live in Maryland, but work in DC, with an office in Vienna, VA. I'd either like to set home points for all three of those, or broaden the radius from the middle location to encompass the outer 2 locations.
I'm sure this is a freaky edge case, and will likely never be implemented, but if I could multi-home, and have a filter that included locations near any of the three, I'd be gold.
In many ways this would be similar to how Foursquare rolled out.
Perhaps you can identify scouts in particular cities who have expressed their delight in your service or create a signup page for people to get notified when you arrive in their city.
I've been participating for a couple months now and always kick myself when I forget to take a pic of my food – not only is this fun, but it's a great way to keep track of where you eat out and what you eat.
I think this is a great idea as well. I'm not sure if the end goal is to have reviews of dishes. If so, I think you need a more structured approach. A Yelp with menu reviews.
But I would suggest targeting one-or-two local markets - I typed in my city, got invited to be "first", service over for me.
Localizing gives you huge advantages for PR / marketing / user interaction / etc. and you lose very little in the "getting traction" state.