Hi, I have a few very hairy rabbits, I never have any problems with smell nor have I clean them, they clean themselves very well. It is your toilet that needs to be improved, just throw away pee pads and never use them again. They simply not suitable for rabbits and they also can chew on plastic which is dangerous because small plastic pieces can cause blockages. So your toilet is good size no need to change it, just get wood pellets and put about 1 inch layer of pellets in it and cover with hay. You will need to empty/rinse/refill her toilet twice a week. Some people do it once a week, it depends on how much your bun drinks so how much she will pee.
Baths are last resort, I would only use butt bath if rabbit is seriously ill and weak, maybe old etc. It is hard to tell without seeing your bunny how bad it is, from what you described I think that her hair stink now. I would take a little washing up sink bowl would put a towel into it and would add some warm water so just towel is damp but no water in there. let her sit on it for a minute then clean her hind part with that towel, then put her on a dry towel and dry her hair as much as you can. I would use paper towels after that because they absorb better. Make sure her hair is completely dry.
Her feet must be also stinky and yellow, so don't forget to dry them well too.
When you change your setup to wood pellets it will be always dry and she will clean herself. If she has matted hair on her butt maybe you will need to brush and clip some knots. If you can take a pic that would be easier to suggest.
I'll get you some links where you can get wood pellets now