I've found that cruises are an excellent choice for a holiday. Lots of opportunity to rest and relax, for both myself and my wife. The selection of excursions at each port of call usually includes "non-walking" options, enabling those like myself (arthritic and not very mobile) to enjoy as much of the local scene as possible. I can also take on board my folding mobility scooter and use it to get around the ship as well as on some excursions. You get to meet plenty of nice people and I have never had any problem with my PD status. I just tell our fellow diners and they accept and make any allowances for my slow eating etc. And the crew are exceptionally helpful (on P&O at least), example - when they spot me at the breakfast buffet, juggling my stick and a tray they take the tray from me, load up the plate with my choice, find me a place to sit and get me a drink. If you can afford it, I recommend it.
So, we are going to New York for Xmas, we both have family there (in Nutley, New Jersey and New Rochelle NY), but we decided to go by ship - the Queen Mary 2. We were going to fly Economy from the UK but proposed to fly back (overnight) business class to get a comfortable sleep. But the cost of this is not much less than going by sea and you don't have any problems with jetlag, nor having to work out your meds , and you arrive refreshed and relaxed. We dislike flying - not just the flight but the airport hassle and the inability to sleep on overnight trips. The QM2 is the only ship that offers a transatlantic crossing
The cherry on top is that the QM2 carries pets! (dog or cat) So we are taking our lovely Tibetan Terrier, Muffin, with us!! We won't have to leave her for a month, and she will get to meet 4 grandchildren who have only seen her on Skype. We are thrilled to bits with this - costs us an arm and a leg but she is worth every penny.