Chakras are not doors that need to be opened- this is a misconception brought by the misunderstanding of ancient Indian rituals, which consisted of visualizing a flower opening where the chakra is. Kind of like Robert's methods of stimulating a chakra by imagining it's a bread roll and you're tearing it up. They are exercises of what you can do to stimulate them, not literal descriptions of what chakras are.
-End of rant.
You don't have to do anything special with chakras to have access to higher planes, all you have to do is practice and get good at projecting and exploring wherever you land at. To get to a higher plane, you have to exhaust all possibilities on the planes you have access to. However:
All energy work is beneficial for projection practice and mastery. This is because you are developing the energy body, which will help you with maneuvering, stability, and possibly duration when you are projecting. So we recommend energy work as a standard of good practice.