i am currently using two types, both of which include a cable to lock them to a sturdy part of the car. One uses a simple thumb wheel mechanical combination lock, the other uses a key lock. Higher end ones are available with a biometric fingerprint or digital locks, but I don't want to depend on batteries given the way temperature affects the battery power and life. I would not plan on rapid response retrieval from any of the three lock types.
First item: slightly smaller lock boxes (like my mechanical combination one) may not hold the pistol with magazine; i have to remove the mag to store my double stack in it.
Second. in my primary daily use sedan I have the combination lock box cabled under the driver seat, connected to the sat support. I use this one for short term storage, like when I must go into a business that forbids carry.
I have the key lock box in the trunk, cabled to a strong metal part of the car. I use that one if I must store for longer periods, since it ensures totally out of sight storage and two locks (car and box) protecting the gun.
Neither of the boxes will hold my pistol in its kydex holster, something my bedroom box does. It would be really nice to have a cabled box in the car that big, but I am not sure such size is available, or would fit under the seat to stay out of view. I really like being able to disarm without pulling the gun from the holster.
For the minivan, look for some place you can use the cable and push the box out of sight, most likely under a seat.