Michael R, The more you have the students involved with what is going on, the more ownership and interest they will have in what you are so kindly intending to do.
For example, you could have them draw buildings on construction paper and have them figure out ways to make them stand up, creating a village/neighborhood.
Somebody could make a girder-type bridge out of a sturdy shoebox, cutting here and there, and removing the ends, to make it look more like the prototype (researched via www. )
Other ideas off the top of my head: somebody designs streets using black constr. paper; trees get made from twigs as defoliated trees/shrubs.
As a high school English teacher, when given a group of students who needed passing scores on their HSPTs to be graduated, I wrote an instruction booklet, ordered lumber (pre-cut,) and brought to school everything else needed to make an operative and landscaped 4x8' O-gauge layout and a 4x8' HO layout. The unusual stipulation was they could not ask me questions; instead, they had to read the instructions and work it all out among themselves, inluding the measurements.
Many of the stdents had never even seen a tool box (this one was red metal) previously.
Every student who signed up for this after-school project passed the standardized test six months later.
On one occasion, one of the senior boys kept drilling and drilling w/ a battery-powered drill (no electric tools were utilized because I was not a certified shop teacher) trying to make the holes for carriage-bolts to attach the legs. He kept pushing and pushing, but no hole(s) resulted. Even the smell of burning wood arose from his efforts. Eventually, the battery needed recharged.
Then, one of the girls in the class asked him if he had read the instructions. He had not. Once he had, he learned about the switch near the "trigger" that allowed "Forward" and "Reverse" drilling. Do you think he will ever forget that lesson?
Have fun, sir, and let your imagination run wild. You will surprise yourself with all that can result from such out-of-the-box efforts!
FrankM