I have a bit of a conflict of interest here, one of my current players ALWAYS (at least three times per campaign for the last 8ish years) tries to do this kind of thing. As both a player and a DM it gets on my nerves. I am trying not to see you as pulling what my group calls a "Ken Maneuver" witch we would define as "going off to do your own thing then expecting it to perfectly dove tail back in at the climax of the adventure."
Look at it from the other player side. Let me tell you about the great kobold round up...
it was a few years ago right around the 3.5-4e change over. It was a 3e game and we were teenish level. The DM had in an earlier level (maybe 3rdish)set up a group of kobold mercenaries for us to fight and instead we ended up making friends with them. It was great and an epic moment of RP. We then talked to them a few times. They were like 200 MM stat kobolds, and 25 special champions stated out with levels, one of them was a dragonwrought kobold who used some trick to have epic feats.... anyway back to the adventure in question, we were about to be invaded by a shadow elf army from the moon. They were going to land on shadow dragons at sun set and wreck the capitol of our empire. The seven PCs all talked and came up with what we thought was a good plan with only hours to go, then his sorcerer teleports away without a word. The rest of us were ready to 'time jump' to the fight, but not ken.
Ken had decided to go get those kobold mercs and bring them into play. That sounded kind of cool, but to do so he had to teleport to were they last camped, then cast spells to divine where they were, then fly to catch up to them, then talk them into helping (not exactly easy, it was WAY out of there league), and finding out they were on a job against some gnolls. SO he (still flying) handles the gnolls with his biggest badest spells, so they could complete that contract then come to us. Then he realized he couldn't get them there in time. So he takes turns teleporting umpteen kobolds at a time to us... end result he was almost out of spells and we had a couple dozen low level allies, oh and we couldn't play out the fight because his side trek took almost 2 hours and we had to call it a night.