The problem is, "hard to reach areas" very often create mechanical locks that trash a bedding job. We've all seen those bedding jobs, amateur at best and at worst. Those hard to reach areas should be filled with clay or kids playdough first to eliminate them from the equation. Any pro out there knows this, amateurs don't.
Yep..the best way to get out of trouble is to never get into trouble to start with.
Play Doh is my go-to for filling holes, slots...anything potentially troublesome. It's easier to remove than modeling clay, too.
There's a can of Sherfab's excellent 225 non silicone aerosol mold release agent on the shelf here...though I can't remember the last time I've needed to use it.
As you mentioned, Partall is an excellent rust preventative. On blued receivers on hunting rigs, I warm the receiver with a heat gun and then brush it on with a soldering brush. After it cools, it's buffed and warmed up again. Works great for protection...especially on rough matte finished actions like 700's.
Good shootin'
-Al