I’ll put this together off the top of my head East at Elizabethtown to Grand Tower. Well, of course there is Elizabethtown with a couple of restaurants and a Gas station. I’m not sure if Iron Furnace has water, but it does have vault toilets just West of the trail. Next would be the High Knob Campground. (No camping allowed at the actual High Knob, but the trail is fair game.)
Then onto Garden of the Gods and Pharaoh Campground. Vault toilet on way up the hill and hand pump well at campground. On to Herod. There are some businesses in Herod that may be open. Not sure of any source of water now that the Gazebo well is out of order. You should probably check it out.
Circle B ranch has a spigot they might let you have water from just across the street from the trailhead there.
Then Eddyville. The Café right on the trail in Eddyville is great, and the Shawneemart just south end of town is a short walk to a convenience store.
I think the next might be all the way to Ferne Clyffe state park. Nice tent campground. Then short walk to Goreville with a couple of fast food places.
Giant City has Campground with HOT showers, 2 miles further West is the Lodge with excellent all you can eat chicken. Makanda is next with a deli & ice cream. Next is Alto Pass with a park with a porta potty, and a couple of cafes. It’s a long slog to Grand tower from there. The Pine Hills campground is pretty far south of the trail and at the bottom of the hill. I’d not want to do the extra miles. There is a small campground at Devils Backbone.
There are plenty of creeks for water if you have a filter that usually are flowing unless the drought is pretty severe. I’ll update it if I get some more info. on the well at Herod or water at Iron Furnace.