Incas were not writing at this point. They had a knot system.

To remind people who are what, Aztecs (Mexico now) were North American in today's term, Maya were also North American, bordering Central America (Yucatán peninsula in Mexico) and the Incas were all the way down in South America in Peru.

Meso American is a weird term that does describe the Aztecs and Mayan people... Historically. But, not the Incas and it doesn't really give you the full picture of what we consider to be located where today--which makes people confused about the differences between the three.

Another quick distinction is that Peru has some extremely old cultures that most likely are the far past ancestral peoples of the Incas (with some cultures being a whopping 5000 years old at Caral), but the Incan Empire itself at its height only lasted about a century before being met with the Spaniards and disease.

Kinda same goes for the Aztecs whose ancestral people were influenced by the ancient Mayans (whose archaic age was 4000 yrs ago), though Mayans themselves also stuck around. Anyway, the Aztecs at their height only lasted about a century as well before the Spaniards and disease.

Mayans were really the older culture out of the three that at least seems to exist as a singular cultural entity between the Incas and Aztecs in archaeological records, their cities seem to have been around for millennia. But unlike the Aztecs, the Mayans had their heyday in the past and were a shadow of their former self in comparison to the newly invigorated and growing Aztec and Incan neighbours.

Let me clarify by saying that, it is not my own opinion that he should have kept going or that he needed to continue the wars. My comment above is instead suggesting what he felt he had to do.

Ceasar was in a hole of his own doing. This tends to be the case with those who push their luck with war, walls start coming in from all sides and leaving Gaul certainly wouldn't just stop the conflict he had begun. My point above was simply suggesting that Ceasar FELT he needed conclude the war, leaving no ghosts to haunt him.

Aas /r/PDV87 noted below, Ceasar was in many ways running on bought time. He was already operating far out of regular roman juristiction and who knows what he actually felt about being in Gaul--perhaps he felt it was not safe to return to Rome until he had settled what he had started in Gaul.

It had in many ways become his war, and that is reflected in his rejection of adhering to the senate.

He instigated the war, and Vercingetorix was the signage that it wasn't over. It could be that Cæsar continued the war fearing the newfound Gallic forces would follow him right back to Rome. Or worse, grow and reclaim all of Cæsars conquest.

Either way, Gaul was a place of turmoil. It would unlikely simply be peaceful and not react had Cæsar left.

I'll be honest. This post is written more like a revisionist question. As in, it sounds like you want there to have been more to central Europe during this time, and the mystery and lack of information about it, is the "evidence" or "feeling" you have of them having ties to the mysterious sea peoples.