Lake Greeson and Crater of Diamonds can fit into the same Glenwood-area trip, but it helps to be honest about the kind of day you are planning. This is not just a quick photo stop. It can mean digging in the sun, changing clothes, eating outside, checking lake access, and keeping kids from getting cooked by the afternoon heat.
The upside is that it gives visitors a full southwest Arkansas day without needing a big city itinerary. You get the oddball Arkansas experience of searching for diamonds, the lake-day feel of Lake Greeson, and the small-town route through Murfreesboro and the Glenwood area.
If you are staying in Glenwood, this is a good way to stretch a Caddo River weekend into something bigger. If you are only in town for a short float, save this for another time.