First... Check local laws. These will vary widely by state. In VA you can't have loaded rifle mags when transporting long guns. Pay attention too when it comes to the following:
- some states have laws regarding "hidden compartments". A disgruntled LEO could stick you with this if it applies
- also think about how often you go into "Blue states". It would suck to forget you had something
Second... And before you mount anything, take a class in Self Defense... Good ones will include defending yourself from a vehicle.
Third... think about your climate, and how it impacts ammo. In VA, we have humid summers, as well as winters that go warm/cold quickly. Cycle your ammo regardless... With frequency depending on your climate. Don't stick stuff in places to hide it, and not touch for a year or so.
Lots of options for mounted holsters up front in the Hundy (inside console, outside console, under dash, drawers, etc). My fav is the maxpedition hook and loop. Allows for multiple mounting locations, is not specific to any handgun, and cheap ($15)
IMHO, galco shoulder holster is the way to go. Short draw from drivers seat to drivers window vs. Two handed attempt to get into your console. Allows you to train how you plan to use it, even in the confines of your own home.
Just a few things I use to guide my decisions on these.