This module had lots of potential, but, for me, the layout and format made this module very difficult to run.
Positives: Interesting locale, wide range of choices for the PCs to explore, a wide variety of encounter types to challenge the players.
Negatives:#1 Layout. The encounters/areas were laid out in an order based on the map on the inside of the jacket. Very little rhyme or reason for the way they were laid out on the map. Then, add in the fact that there is a timeline (on page 11- 1/3 of the way though the book.) for the encounters that essentially goes A_B_K_J_I_G_E_C_L_H_I_F_M, and you have a lot of flipping back and forth. The Fort, which is labeled "A", is put in an Appendix in the back of the book (Map on inside front cover.)
#2 Railroading
#3 Adventure Design Flaws-I felt the random encounters in the vale were simply too easy for 6th level characters. The encounters in the final "dungeon" were problematical.