The load that looked good
$2.50 a mile sounds fine. So you take it.
One owner-operator on a trucking forum ran exactly that: 300 miles at $2.50 a mile, with a cost of about $1.60 a mile, before paying themselves anything. What was left: about $270 for a full day of work. And you own the truck, the insurance and the risk.
Add deadhead and factoring, like the example load, and it gets thinner.
That's how a lot of owner-operators go under. Not one disaster: a hundred loads that each lost a little. Not knowing your true cost per mile is one of the reasons most often cited when new authorities don't make it through year one.
Forum numbers: TheTruckersReport, cost-per-mile thread.