UPDATE: I think I have figured a way to make a standalone. I have created a way to do it via Batch (.bat) I need to take it into further testing for security and fail-proof reasons but I think I'm on to something. I'll update again once I have tested this fully.
Actually the easiest way to do it is:
1. Open the game in RPG Maker (obvious)
2. Go to File>Compress Game Data
3. Check the first box so people who download it can't edit it. Check the second box too if you used anything from the RTP.
4. Upload it to a storage website (I prefer MediaFire).