Hi,
It is "Possible" to back up a dingy, attached to the motorhome a few "INCHES" not really feet. You might need to do this if you end up to close to the gas pump or something. Any more than about 4" you would need to at least release the buttons that allow the hitch to get smaller, then back up the RV about 5" and then try pulling away again.
It is better to just give up, separate the RV and car, then move both and hook up again.
Yes taking the car for recon is a great idea when you arrive at a National Park, and want to find a empty 30' site, or something.
If you are spending the night someplace, and can get a full hookup with pull through, normally you can leave it hooked up all night. Sometimes I unhitch to go get dinner, then hook up that night, then am all ready to go in the morning. No need to kneel down on the wet (damp from dew) grass or pavement then hook up in the morning.
Always remember to unhook the safety cables last. Once I saw a Bronco that was unhooked safety cables first, and it rolled away, because the driver had not set the parking brake before taking off the two hitch arms. It was only a short hill, but still the owner had to open the door, jump in, and set the parking brake. I also did the same thing with my 1500 pound Manx buggy. However I was in a nearly level parking lot (Albuquerque hot air balloon fiesta field) and it was easy to hold on to it while setting the parking brake.
Fred.