I've paddled from Whitton Crossing downstream through Pocomoke City, but never beyond, and never in a single trip.
The Pocomoke River Canoe Company in Snow Hill, Md runs shuttle to Whitton Crossing and, importantly, trims up the strainers between Whitton Crossing and Snow Hill.
This section has moderate to little current, and even though it gets trimmed usually requires some out-of-boat timber crossings and a fair amount of maneuvering and limbo-ing.
By the time the river reaches Snow Hill, it is already tidal, and the tidal influence grows as you proceed downriver. So if you are paddling out to the Bay, you will have to fight an upriver current at some point.
According to a local guidebook (Gertler), from the Delaware line to Whitton Crossing the river is channelized. I expected there would be lots of downed timber to negotiate, but Gertler makes no mention of that.
Adding up Gertler's time estimates for the various stretches along the entire way from the Deleware line to the Bay, it looks like it would probably take 20 hours, so bring your lunch. By the way, Gertler tends to paddle faster than most paddlers.