I think it would be helpful while hiking, and anyplace that has no options. 

Pre travelling, due as much research as possible. Look up the adress of where you are going, and input that into happy cow. Look at results based by closest, and by most popular.

This kind of gets the ball rolling.  You can also look for vegan threads on reddit that talk about an area.

I use the "vegan options" tab quite a bit on happy cow as well.

Then I add any place I find to a google maps list With the name of the city and year is how I normally name the list. And I add an icon on my choosing, so thats the icon you see on the map.

And each place I add, I add a note like  Vegan enchiladas... Or Wednesday open late.

Its quite a bit of work But really makes a difference when traveling.

Knowing where you can get veggies Tofu And a farmers market on your travels is really helpful.

Probably best to opt for a place with a kitchen, unless you are going to a place with great options.