This is the basic structure I use. Returning a string should be pretty straightforward.
Picker.route('/getData', function (params, request, response, next) {
// Fire our response
// You can set any headers here
// response.setHeader('Access-Control-Allow-Origin', request.headers.origin);
// Set your status
response.statusCode = 200;
// Send your response
response.end('Got the data!');
});