Rusty will only decipher the journal when enough pages have been gathered.
Unable to Unlock a New Location?
Here's a list/chart of Egyptian Quests. If you scroll down to the most recently completed location, the next row will tell you who opens the next one for you.
For additional reference, this game has a pattern of ALWAYS needing to speak to someone, somewhere in order for new locations to open. Though the pattern can vary, seek out speakers in:
Town. Camp. Temples of the gods (even previous.) WITHIN previous mines.
Hope this helps☺