A Word on Other Structures
I have discussed various structures that are designed specifically for Z scale, but there are other items available. In particular, bridges made for N scale can often be used in Z scale. In fact, the factory-made layout forms available from Kibri and Noch are usually designed to be used with either N or Z scales.
If you have a sense of adventure, you can try scratch-building your structures. This process can sound intimidating, and it is not for every one, but it does allow you to create the exact structure you had in mind. As an aid to this process, a scale rule that shows Z scale dimensions in feet is available from IBL of West Bend, Wisconsin, to help you construct structures from scale plans. This rule can also serve to help you determine if a non-Z scale item is way out of proportion. For example, in retaining walls, blocks of two feet by three feet might not be obvious, but a stone retaining wall with rocks 15 feet across is out of proportion and will probably distract the viewer. If you are not sure about the size of things, go out into the real world with a yardstick and measure a few things.