I need to drill into the wall and ceiling to install a closet rod and
also some smoke detectors.

Generally, these items are held up with short screws and plastic wall
anchors. Wiring is run thru the center of the studs which should give you
(even with 2x4 [3.5"] framing) at least a good 2" from the surface of your
drywall to where the wiring may be. If you stick to 1 1/2" or shorter
screws and plastic anchors, you should be fine