Hi Robbyn,
Here are a couple of things we've made for schools and school gardens that are really beneficial:
Most of our school gardens are raised beds. We have tried everything between them for walkways, and are finding that either grass with walkways wide enough to mow, or a thick layer of weed cloth with a thick layer of gravel ( 1/4- or crushed granite) work well to keep weeds away. We love our weather stations, which is a design from
Life Lab. If you are able to go all out, make raised beds out of something more sustainable than wood. Corrugated metal with wood around the top, concrete blocks with filler (I can't think of the actual name for the life of me right now....), etc.
Worm bins- we've also tried them all and what works best for us are smaller raised beds where we can compost food directly into and mix in the browns and greens, then cover and lower the hinged lid back down for an in-situ worm bin. None of the plastic things that need way too much maintenance.
Shade! Build some sort of covered seating area and make it round! You can stand in the middle while kids sit all around the circle. Those circus tent type things work well and you can get really heavy duty ones that anchor into the ground to make them more permanent structures.
Hope this is a good start!