Gold coins so people can steal them from you in this doomsday scenario? Gold is about as useful as monopoly money when facing a gang of people that will just kill you and take whatever they can.
Still, better to have them than not. Of course you're not going to walk around with 3 kilo gold chains around or tell people how much gold you got.
With gold, you will be the gang.
Only if you can persuade the gang they can't get more gold from killing you than working for you.
To build the gang you must recruit where `new-recruit-power < total-gang-power`. Since to start you are the only gang member, you can only recruit one dude who is 0.75 your strength. Now the gang is 1.75 strength, so you can go after another dude who's really strong, say 1.25. Now your gang has a strength of 3. Eventually you will be able to swallow up whole other gangs.
That is not at all how anything works. What is "gang power"? What factors contribute to it? Manpower, wealth, weaponry, or what?