If you want to keep the battery area rust free, get a sealed Optimal type battery, else rain and wash water will wash battery acid off the battery top down into the depths below it, and that is known in 914 circles as the "hell hole" that is where fatal battery rust can lurk. If this is all original then I assume the car was garage kept, and saw little rain. the factory even had a recall on these car cause the battery acid not only rusted the body, but also ate up the nylon fuel hose that sits under the battery tray making a fire hazard.
the recall included replacement of damaged fuel hose and a plastic cover for the battery top. You don't have the battery cover shown in the photograph. The cover would be another solution other than a sealed battery to prevent acid damage.
the roof appears very pristine, to keep it that way I would lay a big fluffy beach towel over it while stored in the runk*** to prevent the runk lid's framing from rubbing the texture off of it. The roof can at times rub on the runk lid and it damages easily.
Also the dome light can sometimes get very hot and can melt part of the vinyl upholstery so don't leave it on long, or best yet get an LED lamp, LED lamps are made that fit the stock housing and they give a good deal more light and don't get so hot.
at the gas station don't leave the gas cap on top of the expansion tank and forget about it when you close the frunk***, else the cap can leave a bad impression on the tank and lid!!!
***by the way the front trunk is called a "Frunk", and the rear one a "Runk".
