My boy has impressive recall but I wouldn't let him off the leash for a week at a cottage. I feel comfortable taking him for a walk off leash, most of his walks are off leash anyway. But, as you say, he's a dog. I would not trust him to stay at the cottage with me without very close supervision. Or a tie-out. Or he stays in the cottage.
I am keen on whistles now, since they work so well for my dog. Have you tried whistle training? What is the absolute best reward in the whole world you could offer your dog? That should be his reward for coming to you. If you don't trust the recall you have now a method to revamp is to change it up for another cue, such as a whistle instead of whatever word you use now. Or a new word.