Take it from a truck driver, tires are not something you can scrimp on. I thought my boat trailer tires looked good while preparing for a 2200 mile loop last year. Perfect looking 12 year old tires are junk, when they blew at 1 AM in Weed Ca I spent the night behind a choke and puke. Sleeping with 1 eye open until 4:30 was not my idea of a vacation. Fortunately my marginal spare held till I got to Carson City where all three were replaced. Tires, battery’s, beer and coffee are not the place to save money. Depart for your trip when your rig is ready, your level of enjoyment will be a reflection of your preparation.