Reading through Mummy's mask, I kinda liked it, but it would perhaps not be a good fit for every group. I especially liked the first two adventures in the AP. There is a lot of tomb exploring and the amount of flexibility, sand-box feel, is very limited. But in this case, the events become rather monumental and move rapidly, so I am not sure how much the PCs would notice that they don't get a lot of explore time in the large world, because they are too busy dealing with rather immediate threats, such as the living dead arising and attacking, or a swift onslaught of flying pyramids, or the like. It certainly captures a certain flavor of adventure, pulpish with movie-like sensibilities would be how I would describe it. I am not sure though how sustainable such a flavor (rush here, rush there, danger, danger danger...) would be over the course of a year long AP. If you could somehow condense it, it might work better, or if you could play frequently so as not to lose the urgency.