R.K.
When we moved from California to Wisconsin 18 yrs ago I had a similar situation. My kids were younger but Halloween kinda jumped up at me. I had so much going on I totally forgot about costumes ect. My daughter was about 8, I took a hair net and bobby pinned rollers into it, had her put on her bathrobe and tucked her hair up in the hair net did a smear job with some red lipstick and she went out as a distressed housewife.
One year I dressed all in pink and put a child's resin chair on my head (could also use a shoe) and I was a piece of bubble gum stuck on the bottom of a chair.
Another year I took a big box, cut off top and bottom, wrapped it in Christmas wrap, put a bow on the front, stapled straps for my shoulders and dressed all in black and I was a walking Christmas gift. If the box is big enough you could just cut in arm holes and one for the head and slip it over her head.
I hope this helps. Have fun