My daughter Sirrahsim, (Missy) had a similar situation with her fraidy cat Boomer. She lives in Japan and it is midnight there right now, but she might have some suggestions because now, Boomer is a real cuddle bug - though still shy around strangers.

I would NOT try forcing Kelly out though - she must still feel the need to be safe and prtected and I would hate to scare her even more Sounds like she is going to take lots of patience but some cats just do ....she will come out on her own time. I clicked put out food only when you are around - but that was just what occurred to me - not sure if that is really good advice or not.