The answer to this problem for Yellow Weld was to rent a storage unit that allows us to store our tools that we don't need to keep on the trucks for field work and allows us a space to fabricate things like our handrails and tables. There are downsides to a storage unit as a shop. First off, there is likely no power in the unit, easily remedied because we always have our welder/generators on the trucks. Second, the lighting is horrible if it even has lights at all. Luckily, I have a million flashlights and work lights, so that wasn’t the end of the world for us.
It can be against policy to weld in a storage unit because of the liability of catching something on fire, luckily for us that isn't an issue where we are but it's worth keeping in mind. We didn’t have a large unit which meant we couldn’t have a big flat, and extremely useful, table. So we generally worked on the very unlevel concrete floor which makes keeping projects flat and square a challenge. But we made it work with what we had.