when btg back to 200$ 
you tell me! 
With this network upgrade, will it reach the December 2017 value of $ 300? Should the wallet be upgraded due to this network update?
I wont try to predict the price, hope it does!
also, if you are using BTG core wallet, yes you must upgrade this and copy the wallet's dat file over https://bitcoingold.org/downloads/ That's it!
If I hold BTG using the Ledger Nano S is there anything that needs to be done before the Network Upgrade?
Nope, just leave the BTG in the wallet on the fork date
So pathetic. Scamming ppl with useless premine shit-fork. And laughing when they ask if they get their money back. This is destiny of all shitcoin forks with only purpose to enrich owners.