The easiest way to get an cycle is to play on Polo Grounds, since the corners are very short (good for HRs) and the center field is extremely long making triples very doable on shots to the gaps. Pick a team with good hitters (Yankees, Angels, etc) against teams with weaker pitchers (Rays, Tigers, etc) on rookie. If you have lots of sluggers on Diamond Dynasty, using them on Play vs CPU might be even easier.