If we sell a vehicle do we have to list that as income talking about a travel trailer and a pick up truck

Assuming you did not use the vehicles for business there’s no tax liability if you sold them for less than you paid for them. 

If you sold the items for more than your cost basis, you have a taxable capital gain.  

Your cost basis is what you paid if you bought them new or used.  Your basis may be reduced if you used the items in business (depreciation) or if you were in an accident and pocketed the insurance payment instead of repairing the vehicle, or if you took a casualty loss on a prior tax return.  If you received the items as a gift, your cost basis is the same as the giver's basis.

Most of the time, personal property is sold for less than you paid for it, so you don't have a capital gain.