There is a vague idea going around that Van Til was not able to clearly communicate his thoughts, and he needs secondary material to properly explain his position. If one starts with his work on the Reformed Pastor I think his position will be made clear in his own terms. After that his Christian Apologetics should fall into place.
Twenty plus years ago Richard Pratt's Every Thought Captive was considered a good entry-level text. I'm not sure if that has changed in a world that craves change for change's sake. Dr. Pratt also has a paper correcting common misunderstandings of CVT, which I think is online somewhere.