OK, this is what I would do, other opinions are available and possibly equally valid.
1 A thorough visual examination, particularly the camera,gimbal, ribbon area.
2 See if the crash battery will take a charge without issues.
3 Fire up the Phantom and in particular look for video feed an gimbal response, look for any warnings, and obviously take props off.
4 Repeat 3 with known good battery if probs with 3.
5 Re shell. Personally I would have no problems with a reshell, but depends on your confidence/skill level.
6 Re boot and troubleshoot, probably at the earliest opportunity during the reshell, ie before complete assembly.
Sorry if this sounds a bit patronising, you may be well ahead of me.