Is this for inside the RV or outdoors?
For inside, mosquito nets are the best thing as well as some citronella plants near doors, like lemon grass.
Here in Spain a popular product for going out and repelling mosquitos is Nenuco agua de colonia (¨perfumed water¨?), it is sold in the baby isle in the supermarket so must be delicate enough for their skin?
I bought a bottle for my mum during her last visit and it worked quite well.
She has had success with the bracelets that have the high pitched buzz before, definitely the thing that made the most difference. Hers was radarhealth but there are more brands available now. I don´t know how well these mix with dogs though, perhaps the sound may bug them? I´m not sure.