AB dynasty value (1 Viewer)

I've got Antonio Brown in a true dynasty league.  PPR.  Looking to move him before the bottom falls out in Pittsburgh and looking for a RB and/or picks. 

RBs are very hard to come by in this league but what RB should I be aiming for?  

Top WR is just beneath the top 5 RB.

Not in any order-after Bell, Johnson, Kamara, Elliott and Gurley.  Hard to make a fair straight up 1 for 1 trade. you probably would have to get a 2 or 3 for 1 to make a trade.