I love cruises. I can find cool and shady spots (I burn and overheat easily), you don't have to leave the ship unless you want to (sometimes it is fun to be on the almost empty ship) and there are bathrooms all over the place.
If you want to, you can cruise cooler climates. I heard Alaska cruises are fantastic. We have always done the Caribbean - I found Eastern and Southern best.
I did not do well at the Mexican resort as there were very few food options. on cruises, the food was pretty standard fare and I could always find something that would agree with me
Oh and my hubby is 48 and I'm 45 and we find these fun. There are lots of things to do