I've noticed variant map data depending on the layer you click (i.e. US Topo, Topo, Streets, Imagery). The Topo and Streets layers appears to be mostly up-to-date. You are correct that the US Topo layer is "way outdated", more like 30 years. What matters most is the accuracy of the land ownership and access rights layer. Of course, the start-up page makes you accept a "use disclaimer" releasing AZ Game and Fish from any legal responsibility for the use of its site. I guess that's their way of saying, "Not our problem if you end up in jail or with buckshot in your rear-end."
This is my gym. I have to travel down a bumpy road to get there. There are no treadmillls, no machines, and no personal trainers. I walk..I run..I breathe the fresh air. I can go any time I want, as much as I want and there is no membership fee.