The approximate path to the summit is shown on one of my pictures or here (http://4.bp.blogspot.com/-5UwxOS7xl8c/UsW1mGR2nfI/AAAAAAAABow/5DmYLe63MW8/s640/Crokis+Taborno.jpg).
The access has been described as "not overly difficult - a constant UIAA grade I/II - but very exposed" in one site (http://www.summitpost.org/roque-de-taborno/278213). Other sites rate the crux as UIAA grade III (http://tenerifevertical.blogspot.dk/2014/01/roque-taborno.html). In my view the short crux, which is close to the top, should indeed be graded at UIAA grade III.

The descent is more difficult than the ascent! It is important to remember, or better to mark, the upper exit from the crux during the ascent. Otherwise it might be difficult to find the easiest and safest descent later.