If you're on a Mac then i can recommend Dash app for offline docs libraries. For me it's completely different experience to code offline (very enjoyable). More thinking involved - less Google/SO.

Can you say more about how you set it up? This sounds like a balanced solution: you avoid the long time sucks but can still look up needed info.

Sounds like a script with iptables. I believe many consumer routers also support time based internet access