Sorry to burst your bubble... but most hospitals do not have a metal detector.
The Franscican system (St Joseph, St Claire, St Francis and such....) and other hospitals in WA:
Harborview does have one but typically only use it when they put the hospital on "modified lockdown" during evening/nights and weekends.
As for signage you won't typically see any for the main part of the hospitals but you may see them more in the ER entrances.
All hospitals are "gun free zones" and will ask you to leave or place your firearm in the your vehicle so concealed means concealed.
As for WiFi - all hospitals are moving to some form of wireless connections to do their internal connections of becoming less paper (charts, etc).
Congrats - on the baby to be!
Do not OC at a hospital - the hospital personnel will call 911 and you will be asked to leave.