Infested w/ cockroaches...what to do?

Yikes! I'd suggest contact the client immediately. Let them know their pets are well, but there is a cockroach infestation in the house, specifically on the counter, from the light socket, and on the bed. Since you have a repeat relationship with them, this conversation should go well and be easily remedied. Ask them if they can contact someone who provides that type of pet-safe pest control and when they get appointment time, you'll give them access. You could ask them if they have a maid or cleaning service that could follow up after that. (I wouldn't mention the floor unless she brought up other conditions of the home because that's such a lesser issue)

Your profile shows that you do not offer boarding. Other options to consider is offer to take her dogs to your home, or notify her that you cannot sleep in her home given the infestation, but will care for the pet during day & evening, will sleep at your hoe, and return for the dogs the following day(s).