Monkey Spot provides a great structure for building language in a scavenger hunt context, but you can't make your own hunts in the app as of yet. Consider Google Slides for building your own hunts. Though Google Slides is meant for presentations, you also can basically make digital workbooks with the app, and now that inserting photos is possible, you can make the same type of activity as Monkey Spot offers. Just set up a series of slides with text indicating the items to be photographed (good for working on observational skills for students with social learning challenges) and you're all set. Be sure to make a copy of your Slides file before using it with students so you will still have a blank one for your next group. Having the completed work within your Google Apps for Education account opens possibilities for sharing with students and teachers or perhaps continuing a writing project.
Take a look at Monkey Spot and then see what you can create on your own!