How to know when Leak is fixed???

Impossible to say since it's damaged goods. It may not have ever dried out which means you may also have mold.

An interior air-pressurized leak test will find any and all existing leaks. It's not that expensive to have done by Sealtech or an owner can DIY with an adequate blower. Either process is a lot cheaper than repairing a hidden leak and it's consequential damage.

Do it yourself RV Pressure Test.

I put a dehumidifier in the camper for now. I have taken out 2gal of water in 2 days. The toof liner has tightened up considerable. I am planning on trying a pressure test when I have some free time. Concern with pressure test/same with the dehumidifier will be that it is an old super light feather light model and I think I will need to duct tape every window and external access door.

MJO21 wrote:
I put a dehumidifier in the camper for now. I have taken out 2gal of water in 2 days. The toof liner has tightened up considerable. I am planning on trying a pressure test when I have some free time. Concern with pressure test/same with the dehumidifier will be that it is an old super light feather light model and I think I will need to duct tape every window and external access door.

If your test blower moves enough air, any leaking through doors or windows won't matter. Your avoidance mechanisms are showing.

Correct...but won't the air pressure find the easiest way out? Doors, windows, and hatches would seem easier than a leak I can't see with my eyes?

Yes, a big opening will allow more air to escape. Regardless, if the interior pressure is raised to .5 inches of air column, you will see bubbles when you spray the soapy water on the exterior.

You're free to tape up any and all air escape routes, it makes it easier to raise the interior pressure.

What I now do is cover the roof vents from inside, put stoppers in the sink and shower, but I don't fuss with the heater flue. That is a 3" pipe and is open to the exterior. I'm able to raise the pressure beyond 1" of water column so no other methods of sealing are necessary. There is a lot of air coming out the door opening when closed as it is a poorly fitted door. I have plans to make that better.