We recently camped at Carter Lake. The facilities were good - campsite, fire ring and bath rooms. However, they were very crowded. A week beforehand we booked the last campsite at the lake and it was the one with no shade. All the campsites were very close together.
The website claims very little availability and a two day minimum, but depending on who you talk to at the park there are one day sites available on the weekend if you just show up ... or not, depending on who you talk to at the park.