Is it a fully staffed tour, with a Head Carp/Flyman? If it is, All these questions should be answered in your advance paperwork from the venue with your head carp, so you can know before you get there. Hours access will depend on if the house is union or not. You will most likely never get keys, so you will need to leave before the last person does. If there is access codes, they will let you know on the advance.
For FOH, ask what the communication is, most likely it will be by radio, sometimes one that the tour provides. I wore mine at all times, FOH was on channel 5, Lights were on Channel 6, Carps on 7, Sound on 8, Etc. So I had to jump channels every time I made a time check. As far as house procedures go, it depends on what your tour needs. I had a sheet from my parent company that I filled out regarding exactly what we needed to present to the theatres so they knew what we expected regarding late seating, calls, etc.