As you describe it, your trailer would seem to qualify.
There’s no reason it can’t qualify as a second home, if you choose to treat it as your second home. See Qualified Home in IRS 2021 Publication 936 for more information on what homes qualify for the deduction.
As Expert AmyC notes above, a home can include a house, condominium, cooperative, mobile home, house trailer, boat, or similar property that has sleeping, cooking, and toilet facilities.
And bear in mind that home mortgage interest is any interest you pay on a loan secured by your home – your main home, or a second home. The mortgage must be a secured debt on a qualified home in which you have an ownership interest.
