In my experience (6 years and nearly 3000 hours instructional), I always found great instructional value in taking a stude to a disused airfield and adding climbing, turning and descending practice into one useful lesson, i.e how to fly a circuit from 500'agl on the climbout to 500'agl on final then go-around. Makes the initial actual circuit lesson much easier, beacause they've already done it without really realising.
The first place I instructed actually
taught students to fly the downwind leg at a distance from which they could not reach the airfield in the event of an engine failure! Apparently there were "plenty of suitable fields on the south bank of the river" (oops might have given it away there!

) My argument was: "there are plenty of useful metres of tarmac on the north bank!!"
And as for some places where I've seen studes with a CRP-5 out planning the circuit as a navex.....(well almost)......i could go on
cheers