its to easy now a days. you can make a simple cave or ceiling house, kill pigmen for tons of food. the mobs are relitivly tame and the ghasts are to easy to avoid.
more recently i cleared out a neahter stronghold and set up base. i also have on a smp server an under lava hidden obsidion fotress that requires placement of redstone torches in specific areas to open a hold in the lava to get to. that one took me over a week just to do the openeing, i had to use screen shots to know where to rebuild the neather as i worked, i onyl had a few hours a day to work without people around. its been there for months now undiscovered.