I saw this the other day at my local Barnes & Noble. It is really quite nice with full pages of the original journal and Dippers additions. It is a nice thick hardcover. The cover is a good likeness of the animation once you remove the slipcover. A quick recover and a little work and this would be a spot on replica for a REALLY low price.
Check it out!
https://www.amazon.com/Gravity-Fall...&qid=1474599890&sr=1-1&keywords=gravity+falls
Check it out!
https://www.amazon.com/Gravity-Fall...&qid=1474599890&sr=1-1&keywords=gravity+falls