Honestly, I think the type of care depends on each dog! Each dog has their own kind of personality which includes what makes them feel safe/comfortable and cared for. As an example there had been a dog I had been asked to take care of (overnight as well) and the owners had said I could keep their dog in the room during the night but she might whine and bark, however then they had mentioned that their dog does not like sleeping alone. To make it an easy medium, instead of shutting the dog alone in a room, I slept in the same room as the dog so it wasn’t as reactive/anxious. For walking dogs, I typically find it is fun and important for dogs to be socialized to other dogs (this can be tricky if a certain dog doesn’t like other dogs, in which case I go over this with their owners and figure out what is more comfortable for the owner and dog), so sometimes I might like to walk a couple of dogs together. It gives the dogs a better idea of what it is like to be walked as a “pack” and many dogs behave better on walks this way (Shoutout to César Millán). I also think it is really important to build trust between the dog and I, so I do like getting to know each dog one-on-one sometimes, in this case I will just walk the dog with me and build a better relationship with him/her.