Re: Nervous about pumping and daycare :(
I also agree with the Medela. Mine came with the battery pack. I use it all the time in the car. If you are attending a college, find out where the student health is. Ask them for a room to pump in. No use being in either a warm or cold car if you don't have to. With 50 minutes, you should be able to get there, pump and then get back to class.
I have the backpack style PIS and no one can tell what it is. I carry mine around at work and no one has ever asked me what's in it. It's great. Best part, it's all inclusive so you can keep the milk with you and it also doesn't have to be left in the car. (freezer packs included with it).
I'd get it now and confirm that she will take a bottle for someone else. If not, my DS lived on cereal and a sippy from 4m on. Hated the bottle and I was gone almost 10 hours a day. He wasn't the greatest with the sippy but he drank enough to keep dyhrated and then power nursed when I got back.
I agree with feeding right as you are leaving and having them wait to you get back for the 3 hour days. You may want to leave a frozen couple bags of milk in their freezer incase you are ever late. Also a spare bottle for them to use.