I am going by the ESPN draft big board. According to that, Withey, Dieng, and Adams are 6, 7, and 8 on the center rankings and 23, 24, and 28 on the overall rankings. The Knicks would currently pick 24th (25th if they pass the Clippers) so I think that there is a good chance to at least score Adams, if Withey and Dieng are gone. In any case, I would fill the PG with Kabongo if he is available first. It is possible that he will go back to school and that all three of my target centers are also gone, in which case I probably go with Shane Larkin, or the best player available at any position otherwise.
I suppose that a trade up or trade to score an additional pick is also possible, but not clearly needed at this point. I would hesitate to trade anyone currently signed for next year for a draft pick unless it were a lottery pick. Getting another pick below #20 for a current proven player is not a clear win, although I can see the argument for Camby or Kidd for a pick in the #14 to #25 range, but this is more compelling to me only if it meant a clear upgrade in both the backup PG and backup center positions.
Trading their pick and either Camby or Kidd for a lottery pick I can also see. I would not trade Felton or any of the other guaranteed contracts for less than a top ten pick. Even in the top five there have been plenty of draft busts, and below five there have been some jewels (Paul Pierce, etc.) but it really starts to get hit or miss.
If the Knicks fail to make it to at least game 6 of the second round playoffs this year, then I might reconsider this position.