Restricting node access for nodes that are associated with other nodes which have user reference
I don't have enough rep to comment, however, if you are referring to an authenticated user (logged in). You can set the Access Control rules for the logged in user per node. If the user is not logged in, then it is not possible as anybody with a valid URL can view the node.

If you want to hide fields in a content type node. Go to Structure->Pages->View Node (you will have to enable this first in case it isn't). Then create a new variant for that content type and then manually add fields you want the authenticated/anonymous user to see. Make sure you have Context and Selection rules enabled and that admin roles are excepted from viewing that variant. In other words, admin will see everything.