My wife and I stopped at Lake Shel-Oole Campground on our trip to Canada this summer (July 3rd). The campground is a bit dilapidated, but had several spots available that were easy to pull into. Some sites were pull through and others were back in. Most sites have at least electric and some are water/electric. Some sites are also 50amp. There is also a dump on site.
All sites are $25/night. Payment is on an honor system and drop cash into an envelope in a box near the entrance. The park says that it is under surveillance, but we did not see cameras. We saw one Toole County Sheriff's Deputy drive through the park while we were there.
I think we counted a total of five other rigs staying the night with us. If you have kids there's a playground nearby and a baseball field. There are also several walking trails.
We would definitely stay here again if we take the same route to Canada. Very convenient and quiet!
Check out our review of this campground on our blog: https://lower48intow.com/lake-shel-oole-park-campground-an-overnight-stay-on-the-way-to-canada/