Wearable tents and small boats exist, but they don't really feel like a home. Wearable skyboxes meant for quick wardrobe changes also exist, and don't feel like a home. If you use the Firestorm viewer, you can set up outfits and only need minimal privacy to quick change between them.
What does exist are very cheap weekly rentals of land from land barons. This might be a way to experiment with the idea of having a small home if you're not ready to go premium or commit to a larger rental.
You could also just remember to always log in at a LL owned water sim or park, if what you really just wanted was a chance to gather your thoughts and answer messages, before heading out onto the grid. When I was landless I'd keep two SLURLs to hand, one for the deep ocean floor on a LL water sim, and one at the sim where my favorite community did most of its gathering.
It's also possible to belong to a group that will let you set home on group land, once you get involved with something.