Antelope Island is a good one, only 1 land passage in or out, fires on the west side can't be seen from any city, migratory bird stop, buffalo.
Yellowstone would be another good place. Low population, lots of hunting, and plenty of things for the occasional walker to just fall into (would boiling acidic water have any effect on a walker?).
All you guys planning to do a lot of driving need to learn to refine oil and dirty gas, cause you only have about 6 months before it all expires.