Nothing fancy, but it was a great place to stop for the night. Both times I've stayed I arrived after dark and was only passing through, so I opted not to set up the tent and instead slept in my crossover, which is set up to sleep in. The area was well lit at night, and I felt very safe.
The campground: It's small, mostly quiet, flat, and had a decent amount of shade. The area I stayed in had pull through spots that faced the water (a reservoir, I believe). There's a small dock on the water. My site included a picnic table, grill, and water spigot. I'm not sure about electric hookups and dump stations, since I have no need for those things. The bathrooms were clean, and had both toilets and showers.
Booking: The campground does not take reservations, which I think is great, as it allows me to be a little more spontaneous. There's a self-pay station in front of the bathrooms near the entrance to the campground. I stayed here on a Monday night in late October, and had no problem getting a site. The cost depends on if you're there in the off-season or not, but I believe the most expensive fee is $25 for RVs.
The area: Ellis is a small town. If you're arriving later in the evening I would recommend stopping to eat somewhere prior to arriving in Ellis. In the morning, I made a quick detour down the main street and saw a café, a pizza place, and a Mexican restaurant. There's also a railroad museum. The campground is pretty close to the highway; right off the highway are a couple gas stations with fast food places inside.
Cell Service: I have Verizon, and my service was good enough to stream a live hockey game. The campground said it had WIFI, but I didn't try it out.