Either of the above plus Coastal Kippford, which used to be called Kippford holiday park.
10 minutes walk to Kippford on the road, or a nice long, or short, walk through the woods that can take as long as you like as you can go via Rockcliffe. Sandy beach at Rockcliffe which is walking distance, Kippford has the anchor and the mariner for food and drink, the anchor is great for sitting outside on a sunny days. Cafe across the road from the site at the golf course, 40 second ride to Dalbeattie 7 stanes and obviously forest walks.
3 miles from dalbeatiie but castle douglas only 10 minutes away in the car.
I have a caravan there on a seasonal pitch and we love it.
Play park for the kids.
Sandhills is a lovely site but there isn’t a village with facilities in walking distance, well you could go over the clifftop walk to rockcliffe which is a lovely walk but no facilities there.
And yes the steamboat inn is nice too.