No voltage hot to neutral but 120v hot to ground.

This is a 1990 mobile home double wide. There are 2 bathrooms, the one in the master bedroom has the little "test" button and the smaller bathroom does not. We had a roof issue a few months ago in the early spring/summer and water was getting into the bathroom ceiling area (saw it in the light fixture). We have since replaced the entire roof with metal roofing and checked the wiring (all tested good). There is no water in the walls that we can see nor in the ceiling area. We did replace the outlet with a brand new one from lowes with the buttons and a little light. It worked for a day and now it "trips" after a few minutes of using a hair straightener, blow drier etc. The weird thing is that the outlet in the smaller bathroom (outlet has no test / reset button) also does not work. This outlet does work if the master bathroom outlet is working but fails if the master bathroom outlet has tripped. There was no roof leaks at all over the smaller bathroom. There are also two outlets outside, one on the back side of trailer and one underneath the trailer near the water supply is connected. These do not have the test buttons either, so how can I test them to see if they are what is tripping the ground? It is rarely used..Any help is much appreciated. I am not an electrician so I really need help before sinking more money into the place. We are selling it but most importantly I don't want anybody to get hurt. Thank you again.

Hello everyone. I am getting frustrated and I need some help. My house has a gfci in the bathroom. This gfi controls all the power outlets outside and in the garage. The gfi was tripped so I reset it. Tripped again. Went and unplugged the freezer thinking it may be the issue. Still tripped. Unplugged everything plugged into gfi protected power outlets. Still tripped. Replaced the gfi. Still trips. I guess my question is how to continue my diagnosis. Any help appreciated