We have now created a website which includes a TNL time Estimator to aid you in figuring out how long it will be until you can level again. It is only an estimation due to the randomness of certain game elements, but it should certainly aid you in time planning. Also included are links to all of our other guides, which will soon also include a new beginners guide, and links to other common references.
Please let us know if you have any recommendations.
UPDATE: New mirror up: http://leon.dx.am/pages/tnl.htm