You have a dome light already.
Cargo lights require the white/red/white CHMSL assembly. The easy setup is to just tap the dome light wire to power the cargo lights. Then the cargos will light whenever a door is opened or the dimming wheel is rotated to the extreme.
If you replace your dome light with a dome/map light combo, the dome light wiring is taken care of when you bolt on the unit. You will, however need to add power for the map lights on your 2005. IMO, the best place to pick up power is at the dimming module wire light green/orange. This wire is on the battery saver circuit and will turn off a light before the battery is dead if someone accidently leaves it on.