Hot Springs is a fair distance from the Mine, Do you plan on just making a day trip to the Diamond Mine or staying for a day or two? It has it's own campground but there are also CORP of Engineer campground nearby on Lake Greeson. Crater of Diamond State Park
Unfortunately if not boating there is not a lot to do or see on this end of Lake Greeson.
Crater of Diamonds SP should be able to handle it plus they just improved all the sites. Haven't been since the redo but was told they are nice. Hot Springs NP has a campground but do not know any info on length