I think its a little bit of wanting to prop herself up a bit more than take you down. She is taking a very unconventional route of wanting to build a mobile camping van for her living space. People are going to either consciously or subconsciously judge her for this choice. So what she is effectively doing is telling you all the great reasons she is doing this and why what she is choosing to do "makes sense". No one is going to question you wanting to buy a house. Her route on the other hand....

I'm again only basing this on one conversation alone, so it's kind of hard to see a pattern. But from my perspective that's what it seems like.