Complex sentence: After befriending Richards at the instigation of Ian Stewart while covering the trial of Brian Jones in 1968 and ensconcing himself in the band's inner circle, he was soon embedded in the Rolling Stones' 1969 American tour.
Split into simpler sentences: After befriending Richards at the instigation of Ian Stewart while covering the trial of Brian Jones in 1968, he ensconced himself in the band's inner circle. Notably, he was embedded in the Rolling Stones' 1969 American tour.