Beyond the chain, what other parts of the bike do I need to lubricate, and how? Can anyone provide some guidance of how to get to the hubs, derailleurs, brake parts etc, that need occasionally lubrication?
The hubs, crank (if not a sealed cartridge), and headset bearings need lubrication perhaps every 10K miles, depending on severity of service. Brake arms, brake levers, and shifter levers need an occasional squirt of spray lube. Derailers also need to be sprayed with lube and wiped clean occasionally, or you can clean them up good with WD-40 before re-lubing.
Bearing lubrication involves disassembling the item, washing the parts, and reassembling with new grease. This is something that an competent tinkerer can manage, if one follows the directions on, say, the Park Tools website. The tricky details are having the right tools for removing some parts (such as freewheels/clusters) and then reassembling everything with the right torque and tension -- something you want to learn on a $300 bike, not a $3000 bike.