Yep, we got various restrictions all over the place. It's really great that you're concerned and spent some time doing your homework, @cth. Good first move.
It helps to have onXHunt map app, because it shows what's private and what's public. It also tells you who the managing agency is or the owner. Google Earth can help zoom in to find places that look like a gravel pit. And Google Maps can usually get you there.
I find most all rules are about the same (federal and state). I find they are also 'common sense' rules. So, pick out a forest near you and search the maps for a potential shooting spot and go explore. You're bound to find a place that meets the basic 'common sense' requirements.
You're welcome to glean a couple spots of the Trash No Land website map. It only shows public land dispersed shooting locations. It give the GPS co-ordinance and usually offers a word or two about the site.
https://www.trashnoland.org/ There is also a link to the WaGuns map on the top of this page.
I predict we are about to see a closure on all State lands soon. Last year, DNR closed all state lands on Aug 15th (that was a Saturday morning without warning). I thought, for sure, they would be closing all lands to shooting earlier this year because of the current fire conditions. So don't be surprised if it happens any day now.
The most important thing you can do, if going shooting in this fire season, is to bring some fire suppression gear (shovel, a couple gallons of water and/or a fire extinguisher). That and be careful not to shoot into downed logs, trees or stumps (they can spark a fire). The gravel pits that have good dirt as backstops are best (not rocks).
Have a great time and enjoy some forest time! Just use your good 'ol common sense!
Bill