1) The rolling school zone is not in effect now nor will it go back into effect
2) Since the field trip is not on school property there is no issue there even if you are officially on the field trip.
3) YOU CAN NOT carry on the school bus.
IANAL but I believe you are 100% in the clear (legally) to carry on the field trip as long as you stay off the school bus and school property.
Now, most zoos will kick out anyone they find carrying a gun, legal or not. So make sure to conceal and be happy.
2) Since the field trip is not on school property there is no issue there even if you are officially on the field trip.
3) YOU CAN NOT carry on the school bus.
IANAL but I believe you are 100% in the clear (legally) to carry on the field trip as long as you stay off the school bus and school property.
Now, most zoos will kick out anyone they find carrying a gun, legal or not. So make sure to conceal and be happy.