They had a crew round the Moon before going for landing, but they didn't test any of the new landing and ascent operations uncrewed on the lunar surface. Why? Couldn't it be done by remote control? Were they for some reason very confident that the risk with landing and ascent was comparatively low? Was it perceived as too costly? Were uncrewed launches politically difficult to motivate?
Ideas about crewed space missions today often include the preplacemen of a return vehicle and other payloads before the crew arrives. For example the Mars Direct and derivatives, and I think also the orbiting realtime telerobotic Herro mission ideas to Mars and Venus.
Could the Apollo program have preplaced an uncrewed lander, or other equipment, on a site within range of where later a crewed landing took place? Or didn't they have that precision in landing area (they did land near a Surveyor)?