We camped at Fossil Creek in July 2011 and found it quiet and peaceful, inexpensive, owners were very friendly and helpful at finding best diesel and food. A bit older park but nice enough, we only slept and took off early. I probably will use it again on the way to Denver next summer also. Easy to find or can call owners and they are helpful with directions.
Not bad for price but has some problems. WiFi simply will not work except very near shelter house or toward east of park. The dump station is always locked and when you call it takes quite a while for anyone to arrive, then its relocked and everyone else has to beg also to get open. When the camp host are present they are really good at opening it. And they hardly ever open the water so you can't rinse you dump hose. They are really paranoid about that dump station. They also make you move around a lot due to contracted events, really nerve rattling to not know if you have a site. Office and personel are mostly friendly, however ground super (guy who opens dump) is not very friendly. I won't stay long term again, too much aggravation for a hopefully peaceful vacation. Maybe good for a day or two if there is no special event that they hassel you to move. Ask first about special events and IF you can stay in a site for xx days you need. OPEN that dump station and post an armed guard if it's that valuable.