They landed on Earth 150,000 years ago. I don't think anyone realizes how long a time this is, hell ancient ancient Egypt (the Egypt before the Pyramids) only started around 7,000 or 8,000 years ago, and look at what's left. Crusty old ruins (no offense), at their pinnacle, im sure they would have looked what we consider to be relatively modern design.
Hell, the hanging gardens of babylon are only supposed to be 3000 years old tops, and they were supposed to be a marvel of engineering, now lost to time to the extent that some consider it to be a myth.
I think when you take those into account, its extremely fair to say that the colonials built a civilisation not too dissimilar to our modern world, with air travel and metal constructed buildings and the like. No one realizes how temporary our world is and it can all disappear in a blink of an eye due to some cataclysm or technological revolution.
The Raptors, Vipers and even the Rag Tag Fleet were in need of constant repair and maintenance during the duration of their journey. They were pretty much out of supplies by the end, so ditching all the potentially unsafe ships they've been imprisoned in for 4 years sounds fair to me. Plus, yeah, they kept the Vipers/Raptors and support craft because Galactica was empty when it was set on a course for the sun. It doesn't take a genius to figure this out, hell, in one of the last shots we see Adama flying a Raptor around. Im sure they used all the tech until it naturally gave out. The Raptors being the most "modern" tech they had would have lasted longest I'd say.
Just take a look at that graphic. Most of the evidence of our modern society would be gone in only "thousands" of years. Long before the "100,000" year mark where even the Co2 deposited in our atmosphere would be gone, let alone 150,000 years.