If your objective is to find the source of the leak seek out a service center with a SealTech blower. Basically it's a high volume blower that will take air in thru a roof vent and pressurize the RV. Walk around with a garden sprayer full of soapy water and grease pencil and you'll find all the leaks.
There are a few DIY types that made their own on YouTube.
https://rvleaks.com/