Yes. If you look through the Help Wanted ads on this site, you’ll find some advertising for single working RVers. Some are volunteer workamper positions, that don’t add to your income, but do cut your living expenses. Others pay a wage. Depending on the job, it could not only subsidize your income, it could be enough to live on comfortably.
Some work camping jobs are advertised as being for couples because the campground owner wants to let couples know that both partners are welcome. Since many workampers (volunteers) do the job just to have something to do and to feel useful, the parks want them to know they can keep both busy.
Most employers hire single people, not two person packages. The ads stating they have work for couples might actually require a couple (see the next paragraph). But, it is just as likely that they are tailoring their ad to accommodate RVers who travel as couples and want to work for the same employer. They may specify couple in the ad only because the norm is to hire one person and they are willing to hire two people.
Business people also want to get the most value for their employment dollar that they can. If a business owner can provide one RV site for two workers, instead of a single worker, that may be the cheaper thing to do. That said, cheaper isn’t always better and good business people know that. They’ll hire you, as a single worker, in a minute if you show you are qualified and willing and able to do the job.
