One of the fgunniest things I've ever seen-wish I'd taken a picture as no one would actually believe it. At the RIU Palace in Mexico, there was a group of farmers from the mid-west on a tour or excursion of some kind. Most were educated people with wives who were architects, lawyers, office managers, etc. However, one old good-old-boy brought only one piece overall jeans (I'm not sure what the actual name of them would be-but they were bib overalls). He wore them to all of the restaurants and was not reprimanded at all. After all, he was not wearng shorts or flip-flops!
Whether you bring along dress pants or linen summer pants, here is my suggestion (see attached)
Sperry Topsiders, some consider these "boat shoes" I guess because people who get their pictures taken on world class sailing yachts wear these for the pictures. They are quite comfortable, light weight, easy to pack (flexible). They work nicely with the long pants as well as don't look too goofy with shorts or a bathing suit (leave the calf length white tube socks at home though)
I'd suggest wearing linen pants, as they are very lightweight and airy. For the shoes I'm going to push Sanuk again, as I have on earlier threads. They are "sandals" as promoted by their website, but they are closed toe as seen at this link --> SANUK SANDALS Granted, I wouldn't suggest all of those on that page, but they are comfortable, lightweight, reasonably priced, and they are great to wear down the beach. Also, you can get some boat shoes, like noted above. Personally, I'll be taking nice dress clothes also, and I'll wear them if the night is not too hot (though I'm not hopeful). It's nice to dress up sometimes, no?
If you don't want to spend the $$ for Topsiders, my husband has had two similar pairs, one from Shoe Carnival and one from Kohl's. Both were leather and both were reasonably priced and both wore very well. He still wears the pair from Kohls'. The SC pair wore out after a couple of years. Oh and both were purchased on clearance for under $20.