NY 2141 Numbers
I think my SF novels should try to get basic numbers right. Without major spoilers I think I can say that two chests of gold coins figure in the plot. Small heavy chests, but still something a couple of people could pick up.
The gold allegedly in each of the chests is supposed to be worth about two billion dollars. Right now, a kilogram of gold is worth about $40,000 dollars. At that rate, $2 billion would weigh 50,000 kilograms. I don't think two people could pick that up.
Hundred dollar bills pack more buck per kilo. At 1 gram per bill, a million bucks is 10 Kilograms, but a billion is still ten metric tons = tonnes. You will need a super-duty pickup to pull the trailer. A semi for $4 billion, and a small fleet if it's in gold.