For me it's usually just a couple trips. One for the bag of guns, holsters & ammo (think heavy canvas duffel bag, as I'm not a fancy guy), and another for my armorer tool kit (or kits, depending what I think I should have on hand).
The armorer kit(s) are usually because I prefer to use my own tools instead of the ones that are supposed to be at the armory, as I've collected some specialized tools over the years that aren't often available at the armory. (Also, sometimes not all of the other armorers seem to leave the tools in the right place so they can be found.
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I usually don't have to take much of my own ammo because I can use the ammo inventory at our LE range (except when it's not a currently issued caliber, or some delivery hasn't arrived for one or more of the calibers, etc). Ditto all the targets and other shooting supplies. That really saves money compared to many years ago when I patronized public ranges, and I'll obviously miss that perk if I eventually move out-of-state.
I took to leaving my body armor, headphones and range hat in my car, so that saves a trip.
Often other instructors set up a BBQ for the staff for long range sessions, or order out for food, and there's at least water and coffee available for the staff.
Sometimes an extra set of clothing might add a trip to the car (like when working/teaching in really inclement weather, or if I wanted to change out of range gear to make a stop by a cigar club afterward).
For me it's the prep work I do the night before a range session that makes leaving for the range a simpler process.
I've sometimes envied a longtime friend's ability to walk outside his house, and walk over to his own private range on his 10 acres, in the Sierra foothills, and shoot virtually everyday. Of course, my wife would never permit that kind of incessant noise that close to the house.