"let the words of my mouth and the meditation of my heart be acceptable..."

meditation is mention in the Bible. 

It is not such a weird and esoteric concept. 

Mysticism really means the heart of religion.  Praying with real feeling and purpose, rather than praying by rote.

Meditating on the nature of Hashem, studying the scriptures.

It does not have to be some kind of bizarre wierd pursuit.

It is just remembering our real, natural desires to find and experience Hashem in our lives.