The number of pallets in your load will determine the length
Shipments are typically loaded on standard 48" x 48" x 48' pallets.
Truck trailers are typically 48'–53' long, and can hold 2 pallets across.
You can double stack
Load size description:
LTL = no more than 6 pallets (less than 800 cubic feet)
Partial Load = between 7–14 pallets (between 801–1799 cubic feet)
Full Load = 15 or more pallets (between 1800–3200 cubic feet)