Well what a brilliant puzzle. At first it seems impossible but as you work through each stage it suddenly becomes clear what you have to do for the next.
I started doing it at our company Christmas meal as it seemed to be rather appropriate. By the end we'd polished off the first stage and had got through the first word search.
The next stage was the hardest as others have said. Over the next few days I gradually knocked off each of the 19. At one point I thought I was running out of letters for stage 3 (I'd started on that and was backtracking to finish stage 2) but the hint was very helpful here (very cunning I thought) and I finished it correctly. The final two stages were a lot easier.
I was planning to pick up the cache over the Christmas break but other things got in the way. Today I had the day off and so decided to go for it. It was a nice leisurely drive but the final quarter of a mile was more eventful. In short order a cat, a weasel, a squirrel and a pheasant, all decided to run out in front of my car. Fortunately none of these encounters was fatal.
A slightly muddy walk, but the cache itself was an easy find.
This is a definite favourite. It must've taken ages to plan out, and for all the work it takes to solve it is surely worth more than 3.5 stars.