Although we have all our girls spayed (unless they are elderly or have poor health when we adopt them) now, with some of my first groups, we did have a couple of girls develop vaginal bleeding. We always had them spayed after about three days on Baytril (to start clearing up infection and help to ward it off during surgery).
Our vet has always recommended a spay in the case of vaginal bleeding. The baytril may clear up infection, but there's usually something that's causing it and it always seems to come back.
For me personally....I would really consider getting just the spay done, unless one of the tumors is becoming life threatening. Rats should not be in surgery any longer than necessary, so a spay and tumor removal can take some time. My vet is SUPER fast, and even he will say he'd only do a spay/tumor removal if one goes very quickly. As rats age, surgery takes more out of them. It's sometimes best to consider what is most important, and have your vet play it by ear how much can be done at once safely. Also, spaying as they get older, is not a guarantee that tumors won't return. It could help, but in the ones I've had spayed after a tumor appears....they still grew more :**(