Sometimes I use skewers to stack cut up vegges (usually with meat inbetween). I have some stainless wires that I use sometimes and they work great.
Recently I'v grilled, indirectly, several flavors of squash including Butternut, Delicata, Acorn, Pumpkin, Spaghetti, Zucchini, Carnival, and Hubbard. All homegrown. They normally get cut in half and gutted, then S&P. Butter or oil smeared around in there can make nice flavors. A pinch of pumpkin pie type spice can make you damn near nutty. Shredded cheese or Tuscan style herbs, gravy, maple syrup, hot sauce, vinegar or marinara sauce can make squash tasty too.
Potatoes can be cooked 1000 ways on the grill. We like to wedge the taters and throw them in a bag with a little oil and some rub or herbs then shake it around to coat everything before grilling. Planks work too. There's been some really good tater recipes pop up here lately on the forum as well.
The grill basket can cook alot of stuff and you can use foil to make boat or to completely wrap & seal in (steaming) a wide variety of vegges. A cast iron pan or stainless bowl can be used the same way.
Grilled pumpkin stew is good too.
http://weberkettleclub.com/forums/bbq-food-pics/grilled-pumpkin-stew/