I'll see if I can't turn up the Executive Orders to implement REX 84. I've seen them and they mean complete and total lockdown. Constitution and Bill of Rights, bye-bye.
These were consolidated by Nixon into Executive Order 11490 (I can't find the text of this on any "offical" website, can anyone find it?), so that these measures could be put into place by any president if we were under a "national emergency". (Extra credit: How many times has a national emergeny been declared? Have the emergencies been revoked?)
EO 11490 was eventually revoked, but it has been resurrected in EO 12919. The language in 12919 has been toned down, but it essentially does the same thing as the previous EOs. Please look at 12919 carefully, as it is currently in effect. Pay close attention to Section 201, which gives the cabinet heads lordship over various domains in our society. Also look at Section 601, where civilians can be appropriated to work for the government. This is just the tip of the iceberg, I'm sure there's a lot more out there for someone to find if they did some more digging.
Don't take my word for it, please look for yourself.