Also, try BAX Global Freight. UPS and FedEx have truck freight divisions too.
Most important thing I'd do is ask if it'll be carried by the same company for the duration of the delivery.
We ship stuff daily by truck freight at work. Most companies are not nationwide, BUT are in business with other companies. You might ship Saia, and depending where it's going may end up actually getting delivered by another company.
I know FedEx, UPS, ConWay, and others are nationwide. We've had stuff at work damaged when it changes companies through it's journey..... something to think about....