I don't think any boats *used* the Lake Providence route. The Sam Young entered Bayou Macon from the Mississippi River through Lake Providence and returned to the Mississippi River, but only to prove the viability of the route. Those familiar with the Vicksburg Campaign will recognize that most of the other boats this size were operating down the Yazoo River against Fort Pemberton. Grant had only been provided enough transports of this size to carry roughly one division of troops, which negated Grant's original plan to open up the Bayou Macon route and send McClernand's XIII Corps to Nathaniel Banks.
Thanks to you, Bruce, and Robert for all the great information!
Tony