(Via Timebomb 2000)
In any long-term survival scenario, you're going to need tools. Making the assumption that electricity may not be available for any number of reasons, you're going to need old-fashioned non-electrical hand tools. In this spirit, Rogue Turtle has an excellent article on Bug Out Tools.
Pack up everything outlined, and you'll be well-equipped to handle anything around the retreat, from actually building the retreat to building the furniture to go in it.