A local history walk can begin with one modest question about a familiar route. The aim might be to describe a surviving street pattern or compare a present view with an identified earlier image. Keep the scope small enough to explain clearly.
Before setting out, write down what your source actually shows and which details you hope to observe. During the walk, record present conditions from suitable public viewpoints. A modern observation and a historical source belong in separate parts of the notebook.
Afterwards, compare the two records without forcing an exact match. A changed viewpoint, incomplete source information or an uncertain identification may limit the comparison. State those limits rather than filling the gap with an appealing explanation.
The finished account can describe the walk, the sources used and the questions that remain. Its value lies in showing how the comparison was made. A careful small enquiry is often more useful than a confident story extending far beyond the available material.