4 days is a tad long with out being checked on. They could turn over dishes, pull down water bottle, or have an accident.
Is there anyway you could have someone stop in and refill dishes, check on water and make sure they are safe.
If not you'll have to fill them with 4 days of feed, add an extra water bottle just in case, and hope for the best.
I wouldn't leave them that long.My nerves would be shot and I wouldn't be able to have any fun anyway.