I play against a pretty good Ken regularly, I feel as though the most important thing is he can't really get you off him without DP unless you don't react to rolls and since his DP is slow and very punishable you can abuse that. The biggest problems imo are j.A and 2C, Koromaru can make it really hard to approach and some of his attacks tend to clash in his favor.
Usually when they j.A they cover themselves with either 236C/D or 2C or C but if they don't/can't you're free to dash under anti air etc, otherwise I recommend blocking as his mixup excluding oki isn't very strong. Also being Chie you cover alot of air space doing dash->jump so you can j.A if you ever catch him jumping.
On his 2C.. Well there's a couple of things to be done, you can superjump j.C to alter your jump so you don't get AA'd or put in blockstun by Koromaru but that can lose to DP since it's so vertical (but it's pretty much a risky call-out), you can simply block (which is personally the best option), you can roll (risky, very risky) and you can hit Koromaru before his attack starts (usually when I do this it's with 2A to low profile some moves). I recommend blocking and sometimes hitting the dog because when he gets hit it gives you a much better chance at putting Ken in blockstun and starting 5A pressure which imo is very strong against Ken.
I like to put alot of emphasis on instant blocking against him because most of his strings are predictable and his multi-hitting attacks are free bar so you can roll out of his pressure (sometimes into punishes if you catch him going into 236B).
