For myself only: Technical questions regarding the aircraft systems are out, these are covered (or should be) during recurrent training. The check pilot should observe regular line operations, T/O data calculation, pre-departure briefing, standard operating procedures and ATC communications. It is my firm belief that it should be NO different than a regular flight, only that the check pilot is sitting in the observers seat. In addition, I do NOT believe that the Captain should concern himself (or herself) all that much with the cabin crew. A brief greeting, flight details and a general...."let me know if I can be of assistance" should do. Have noticed that some Captains try to micro-manage the cabin. Believe it or not, the company has appointed a cabin chief for that purpose. Leave him/her ALONE to do their job. All in all, a line check should be a rather pleasant experience, at least from my perspective.
Have been doing them for 20 years. Hope this helps.