I can't provide any answers as to why she did anything. We don't even know how she died yet.
My comment was really just to offer an opinion to the OP's question of what she could possibly be doing all day stuck inside a camper, and why someone would lead that sort of life. Although there are other reasons for living that way, I shared my thoughts on what might be behind her lifestyle.
Self-isolation is indeed a coping mechanism -- it is a way to avoid situations that trigger a panic attack. If you've never had a panic attack, count yourself blessed. And I'm going to assume this is the case, because if you've suffered from panic attacks you wouldn't be asking some of the things you presented. A person who is self-isolating does not necessarily want to be left alone, but they feel they have to in order to avoid judgement, or feel guilty that they have mental health issues, or they know they will experience symptoms that they really don't want to feel. Look, it's mental health, there is no hard and true answer that fits every situation.
Anxiety and depression aren't necessarily logical, there are no rules of behavior. I'm one of those fearless women, fierce and capable, yet for several years the only time I could leave my house was to make the drive to work. And that's only after I found a route that could get me there without risking getting stuck at a red light in a left-hand turn lane. I couldn't enter a store, not even to pay for gas. I couldn't go out onto my porch to collect the mail. I couldn't talk on the phone. I stopped attending family events and cut off communication with most of my friends. I kept myself isolated to avoid sensory input and situations that would bring on an attack. And trust me, there were times where I had the conversation in my head about suicide.
Some thoughts about the points you presented:
Why would she go to someone else's property to kill herself? Maybe she thought she was being considerate and this would keep her husband from finding her dead in their camper. Maybe she didn't want to risk being interrupted by a nosy neighbor. Maybe her plan included an action that would be messy and she didn't want to ruin her husband's possessions. Maybe she was searching for a setting that could bring her a feeling of peace. Maybe because it was Tuesday.
In my lifetime, I have lost a grand total of 18 people to suicide. Of those 18 people, 3 of them completed suicide at home. Just 3.
Why would she climb a fence in flip-flops? Maybe because she could -- I have hiked mountains barefoot, it's no big thing if you're used to it and comfortable doing it. We're not talking about some gasp-inducing behavior -- she climbed over/under/through a fence in footwear she was apparently comfortable wearing, something those of us who have spent any time in the country have probably done countless times without giving it a second thought. I live in the city now and struggle with people climbing over my 8-foot privacy fence to cross my yard and I don't even find that odd, I find it inconsiderate.
Here is just one link to an article about isolation and depression/anxiety:
Understanding the Effects of Social Isolation on Mental Health
All MOO based on my own experience and a useless BS in Psychology. If anyone really requires and requests them, I can provide links to any number of sleep-inducing scholarly articles and clinical resources that address the symptoms of depression and anxiety.