The scene in Chrono Trigger when you help Fiona rebuild the forest got me thinking about how Robo got around to his theory regarding the gates and time travel (being a timeline of the world's life), and how he knew about Lucca's past leading up to her becoming an engineer and such, and how it affected her (happens after the fact), and especially, the level of confidence he has from that point onwards about the quest to save the future, and oddly enough, his lack of change post-saving during endgame (think Chrono Cross), provided temporal consistency is in effect.
Basically, he's been around from that point until after the end of the game (including witnessing his future self pass by occasionally, further ensuring him, since the beginning of his job, that he'll meet up with the team again). Meaning he's witnessed the ending with the Epoch flying by looking for Crono's mom, and probably ran into Frog after he's crossed the bridge and got updates to what's been going on (also as the crew has been passing by every visit to 600 AD). Simply put, Robo's not only had the most time to think about the gates, what they mean, and so forth; but he's been witness to all the progress of the game in the process as he's been tending the forest, including the fall/disappearance of the Black Omen, and the permanent closing of the gates after Frog's return to his era; hell, it may be implied he knew where the sunstone went when it disappeared from the cave. Better yet, he also KNOWS he's involved in all the events taking place as he's tending the fields, and if anything, is also anxious to live the events in "realtime" again; and thus he continues the journey when you find him again in 1000AD. The subtle change in his attitude from that event onwards is awesome though; more noticeable in the re-translation patch.
More interestingly, since his involvement with helping Guardia Kingdom during that era and through time, there may have been strict orders to not interfere with Robo's duties with the forest as well; and Fiona's shrine may have been an order of the king and queen of 600AD once the job was finished as a favor. Which can also explain why he was enshrined, instead of dismantled. But during that time, he could have been studied during his shutdown as assistance for the dragon tank's plans, and inspiration for Gato in the rebuilt era of 1000AD.
Events would still play out the same, just with a different context behind it; much like why Lucca's an engineer. In the old present, it was due to an accident crushing her mother's legs. Second time around, not only was her mother caught, but because older Lucca wasn't seen when helping, the machine apparently broke down (actually, it was deactivated in the nick of time, kudos to red portal), and she wanted to know why.
It also got me thinking about the different color portals and what they could mean in another sense (Blue is "The World"'s re-writes (to remove Lavos from the equation/history; especially since 12,000AD when the Black Omen crashes, and Lavos reawakens there, and not 1999AD; possibly preventing Death Mountain/Lavos Crater from even appearing from that time onwards), Red is a personal re-write, and green is "another entity's" (Player's) desire to fight Lavos again, while the Far Reaches/End of Time is out of reach); but that's another thought tangent. Every portal is an opportunity to relive/rewrite history; or to navigate a timeline around a temporal black hole, like Lavos.
Or maybe I've read too much into it? I dunno, it was something I noticed in the back of my mind as I was playing through, and it made an interesting event in the game far more awesome when rethought.