Couldn't dislodge clog with a snake. TLC RV (highly recommended) had to remove a section of black pipe, then a section of underbelly. Opened up a section of waste pipe and found clog where the gray waste line joins the 3 inch black line. Not sure of the cause, but George of TLC thought the trailer may not be leveled properly causing things to not flow smoothly. Sure enough when I checked we were off level by about two inches. Leveled it off and things have been flowing smoothly ever since. Fingers crossed!!
Thanks for the input everyone.