Yes, you're right on the JSON. The way I did my data is by using MS excel, then save it as CSV, then I convert my CSV into C2 JSON format using rexrainbow's csv plugin by loading the CSV into the plugin, then save the array asJSON.
If you want to opt out using 3rd party plugin for your game, then download it using browser object action. The resulting download you can save it as Array.json which is a hard-coded format data that you load using AJAX.
I'm not sure whether is there any better way to do it, but I like the way I'm doing it now because it's error free.