Driver Madness

After finishing the storyline missions, every time i returned to the safe house, there were no weapons available for collection. But weapons are still available at the safehouse in 78' (using era change). Though in 78' , the construction sites have no Dozers driving around, and the Gang shootout doesn't appear anymore.

Another Question, apart from the 4 cheat modes that are unlocked by doing 666, 700, 800 and 900 miles, how are the other cheats unlocked, besides entering codes for them?

Really interesting. I'm not sure about the weapons thing, but for the Gang shootout, I have the same problem. About the cheats, there's no other way to unlock the other cheats without writting them in the cheats menu.