In Oregon and Washington state, trailer parks are far more often utilized by the retirement community than by the transient, judging by my observations. They plant gardens, have large fenced in back yards, and landscaping in front. The ones I'm familiar with are leafy and green.

My sister and her husband owned a 'double-wide' for years (althugh to say that one takes two trailers and bolts them together is somewhat misleading, because the two halves are usually very dissimilar) because he was a construction superintendant and they were frequently sent out of town; living in the park was a safety element when they left their home unoccupied, sometimes for months at a time. After he died, she bought a very large trailer home (four bedrooms, two baths, large dining room) and made a home for a handicapped sister of ours; they lived there year 'round.

In Oregon the rent for the space varies widely, dependent on footprint and location (corner lot or on a busy street or in an overlarge secluded spot alongside a stream, for instance.) Most of the monthly rents seem to range from $250 to $450, which includes sewer and water and electri hookups but does not pay for their use.