As Kelby's 1 yr is approaching I'd like to start switching her to milk for when I'm not around. I work 1 day a week & am just tired of pumping. I will still nurse when I'm here. She does great with sippy cups all the time & ok with bottles when I'm gone.

How/when should I start the transition?

With Rachel I was supplementing with formula so I just increased the amount of milk in each bottle & reduced the formula. Started when she was about 1 year & took about 1 month. Should I do the same with my pumped milk?

You could just do the same thing with regular milk and your pumped milk - mix them together and gradually change the proportions over time.