If you can, take off work for an hour or so to go to orientation. If you can't arrange to meet the teacher at another time. It is important to know your child's teacher, even if there is no problems, you will know who your daughter is talking about when she comes home from K. My son is in 5th grade and I knew each one of his teachers and often emailed them just to let them know that I was very involved. I too am a working mother of 3 (my 2nd starts kindergarten this year)and, no I can't be homeroom parent, go on all of the field trips, etc. but I do use most of my vacation days for sick kids and special school events. My husband does some too.
lastly, teachers WANT to hear from you, they will want to know that you are an involved and loving mom. They are very used to parents who are not - so use any means you can think of to get to know the teacher. You may even call the school before school starts to speak to her via phone. Also, the relationship I had with the teacher was very beneficial for my son... a little extra attention for him and he knew I would talk to the teacher if I found out he stepped out of line. For my daughter entering K, she has peanut allergies and juvenile arthritis, so the day I found out this week who her teacher was going to be I emailed the teacher and CC'd the principal so that they knew that I would be very involved with them on a regular basis, no surprises. Hope this helps.