Easy transfer from cab to cabin was important to us so I enlarged the crawl to a step through. I decided on Accordion Boot rubber which is only available from the US. It has a good automotive fitting on each side. You fit it to the two frames and then make the join with superglue. One side is fixed to the cabin, the other on clips to the cab allowing access to the engine. Neat job if I do say so myself.
I seem to have waited forever for my battery tray to secure and then vent the two large heavy batteries. Tray bolted and glued, the straps and wedges will prevent movement. There is a compromise between needing the batteries close to all the electrical equipment and needing to seal and vent them. The cupboard I am building should achieve this whilst also doubling as a step into the cab.