In a few weeks my hubby and I will be going to Virginia to be with our two youngest grandsons. Their parents are going to be on an Alaskan cruise. The tickets were given to my son by a childhood friend he grew up with.
If your son was equally nice, he would have given the tickets to you and hour husband. Just kidding.
The duration of a cruise will be just long enough for you to spoil your grandsons rotten, while, depending on their ages, short enough to maintain your sanity