This is maybe the only time I would ever say this, but get a cat instead. My grandmother-in-law had a yorkie that died a few years ago. Just before Christmas last year she went to the pound and came home with a 3-4 year old min schnauzer. That dog is going to be the death of her. Turns out the dog has some type of skin condition and she takes him to the vet at least once a month. She can't walk him, so she puts him on a long tether in front of her apartment. He has nipped at two or three of her neighbors (this is a retirement community, so old folks walking around everywhere). Then she can't keep any kind of schedule so the dog ends up locked inside all day long and makes messes everywhere.
I know you are thinking this is just an all around bad/unlucky situation for all involved and you are right. But overall, a cat is much lower maintenance than a dog. If that can satisfy you for companionship, then it may be a much better fit. Also, it will help out catching spiders or anything else in your trailer.