It's well known that Ike was nervous about Wyatt telling any of the Cowboys that he was going to turn in Crane, Head, and the other one (name escapes me at the moment) for the philpot murder. After the trial of holiday and Earp, people knew that Ike was talking to Wyatt trying to reap the rewards from Wells Fargo. I believe this same nervousness came over Ike, now that the word was out that he was starting to roll on the Cowboys. Johnny Ringo was really the last large threat for Ike. Here's why I think it could fit:
1. Ike and Johnny owned 320 acres together in New Mexico, if Johnny dies, Ike gets the land.
2. Ike disappears from the radar in March of 1882, said to have fled to Mexico to dodge the Earp posse.
3. Ike and Ringo had been friends for some time, so Ringo would not be terribly uncomfortable should Ike find him out on the trail somewhere. Which would explain the somewhat relaxed look of the scene at johnnys death.
4. Ike shows back up on the radar in springerville, some 100-200 miles north of tombstone in August of 1882.
I think Ike may have gone to Mexico, but I think he was still keeping tabs on what was going on. I think he was reading of the trouble Ringo was having with the law between March and his death, and was waiting for Ringo to be found guilty of a crime and imprisoned at which time he could find a way to exercise a quit claim deed or other things to get the property from Ringo. However, Ringo having not been imprisoned, Ike was still greedy. Ike travels to the area, knowing where he might find Ringo, they did travel together a lot, Ike would know. He finds Ringo, they share some drinks together out on the trail, and when Ringo falls asleep, Ike pops a cap in him, sets up the scene as if it was a suicide, and continues to springerville.
My guess is, mid July to August is about the right amount of time needed to make way to springerville from there, and do so without being discovered. I find absolutely no information on Ike being questioned, located, or his whereabouts know for that time period..... It just fits...