If your Delta flight is on time it's should be easy peasie. Around that time it's normally not that busy at Non-Schengen - Schengen passport control.
And your plane is most likely a KLM cityhopper Embraer 190 not a 175. You have to be patient as the F70 only wil get replaced by E175's somewhere in 2016.
Last two AMS-KRK flights for me they did leave at B20 with a E190 which didn't involve a busride.
On Monday i will travel to KRK again and am quit confident that it involves no busride (plane is E190)
BTW if your BP says for example B18 prepare for a busride if it says B20; you walk to your plane most of the time
(B piers share gates for example B20/B18, left side B20 means plane at gate, right side and lower number B18 means fokker farm and busride)
Enjoy your polish dumplings!