Yes, this is all possible. What you need to make sure to do is go to the More tab in Cachly, then to Pocket Queries and download your PQ to an offline list. This is the first step. Second, download the offline map that you are needing and you are good to go.
When you have no service make sure to turn on the offline map that you need, and then view your downloaded PQ in the Offline tab. Then you can navigate to any of the caches, view info about them, etc all while offline. The compass and GPS both work while offline.