Drop Box Location: North Denver Rsf - Outside. Drop boxes fit your schedule with 24/7 drop-off for FedEx Express®, FedEx Ground® and FedEx SmartPost® shipments. Package sizes can vary, boxes up to 20" x 12" x 6" are accepted. Select sites also have later and Saturday pickup times. Please visit our website to see latest pickup times. Choose 1-, 2- or 3-day shipping for FedEx Express shipments. Or select FedEx Ground for shipments to arrive in 1−5 business days.