A few more questions.

Who spends $50,000 to overhaul the engine in a brand new truck? That's the whole point of buying new so you're not overhauling anything. Thing is you're going to spend your money one way or the other. Maintaining the old one will take money. A lot of it. Possibly even more than a new payment depending on how unlucky you may be. But maybe not. It's roulette. If you're lucky it'll be a wash.

The new one doesn't eat you alive in maintenance but it has a payment. Cycle into a new one every 4 or 5 years, whenever the warranty is up. Play it right and you can eventually end up in a brand new one that's paid for without having to spend most of your offtime wrenching on old junk. If I was fool enough to do it again I would get a new one but hindsight's always 20-20.

With you exiting the business in 4 years you'll be fortunate if you break even from this "venture". That's just what the odds are.

 

I averaged 35-40k into my truck a year And I don’t think I ever worked more than 46 weeks, maybe running them local might be different, but I’ve done 2 coast to coasts with mine in a month, and I don’t think most people know what it takes to reliably do that