Hello and thank you for your question.
This question is going to come down to specific facts and circumstances related to your case. I will be happy to help point you in the right direction.
Self-employed individuals have the option to claim deductions for expenses that are ordinary and necessary in their course of business (IRC 162). The travel seems necessary and ordinary, so yes, you will be allowed deductions if that is the case.
There are two common methods for claiming travel and meal/entertainment deductions. All people may use the actual method (ie... what are your actual costs?), but self-employed individuals may not use what is called the per diem method with respect to travel costs (Rev Proc 93-50). Meals/entertainment may be deducted using the per diem method or actual method for both self-employed and employee taxpayers. Both employees and self-employed persons may also use the standard mileage rate or actual costs with respect to auto useage.
Here is an IRS pub relating to the standard mileage rate:
Here is an IRS pub relating to per diem:
This is useful for per diem rates:
Now, with respect to your purchase. Should you purchase something that is not ordinary and necessary in the course or your business, you may end up with a (partially) non-deductible item. Some items are referred to as listed property. In a nutshell, you are going to have to keep track of the personal and business use percentages of the trailor should you wish to go that route.
If your lodging costs are covered under normal circumstances, and prudence dictates something to the effect of a very small gas-friendly car for business purposes, the argument that you need a trailor starts to fall sim. You could take a business use percentage (based on miles driven) or perhaps the standard mileage reimbursement for your travel, but not likely lodging for the time your lodging is covered.
To summarize, keep records. Determine, based on your personal facts and circumstances, if the trailor would be deductible based on the ordinary and necessary expense standards and business use % of the trailor (I wish I could do this for you over JustAnswers, but that would not be responsible of me or good for you). From there, figure out your deductions using both the standard rate method and the actual expenses (ie... repairs, gas, insurance, depreciation, applied/allocated per % of business use). Choose the method of deduction that works best, XXXXX XXXXX consistency requirements (ie... you may not be able to flip back and forth between the standard mileage and actual methods depending on / from year to year etc.).
Here is IRC 162, for reference:
IRC 179 and IRC 168(k) bonus depreciation provide some up-front write-off to perhaps assist with your pension income too, but these will be based on the % business use and other specifics of your trailor, as well as your general tax circumstances (ie... is this a business you materially participate in and have a loss?, etc.).
Let me know if there is something more that I can clarify. Thank you for your question.