Water them well before you go and move them back from any very hot window and they will remain in perfect condition for at least 6-8 weeks. Even if you will be absent for up to six months, most of these plants, accustomed to drought in their native country, will be somewhat shrunken but still alive when you get back.
When they do appear a bit shriveled, start by watering them only very lightly at first (they will have to produce new rootlets before they can withstand moist soil), then moderately as they start to plump up, and finally normally when they regain their normal shape.
These low-maintenance plants are the perfect choices for Snowbirds!