I own Kerryon as well and wouldn't have accepted either of your offers either. I think for me, in terms of just RB's, you'd have to offer me someone who sees the majority of their teams' reps, and who is trending upward, not a guy on the downside of his career (redraft by the way). The problem is, there aren't that many guys who fit that bill that aren't already classified as RB1 or RB2 material. I'd rather hold on to Kerryon based on potential opportunity than trade him for another part timer or aging back on the downside of his career. Let's assume the following are off the table: Gurley, Elliott, D. Johnson, Barkley, Gordon, Hunt, Kamara, Fournette, McCaffrey
Then you have guys who are currently dealing with injuries like Cook, D. Freeman, Mixon, McCoy, Ajayi. I'd have to evaluate their estimated return dates before I'd consider one.
Then you have guys like Bell (is he going to play at all this year), Conner (dependent upon Bell), Ingram (I personally don't like the shared backfield), Peterson (doing well, but can he sustain) Howard and Hyde.
Without having to really consider injuries, holdouts, suspensions, etc., the only RBs I'd likely consider beyond the untouchables are guys like Howard or Hyde. But, I'm stubborn and will hold someone with the promise of future potential rather than trade for somebody else's also-ran (e.g., I'm still holding out hope for Josh Gordon).