I wore long, yoga style pants, my husband wore long shorts. We were both comfortable. On our ride there was a mix of short shorts to long, heavy pants, and everyone seemed fine, since you only move at a walk, there's little chance for painful rubbing. I would recommend against jeans though because it gets very hot on the ride and a lighter material would be more comfortable.
If you prefer to ride in regular shorts, capris, bike shorts or skirt rather than long pants that will feel hot and sticky....but you're worried about chafing from the saddle.....just bring a beach towel along with you...throw that over the saddle....it won't get in the way of the stirrups and will provide a barrier between sensitive skin and the leather.
I have read many entries on the MB that say u should wear long pants. I was wondering if the horseback riding in Jamaica is different. I have gone horseback riding in several different countries and states and never wore long pants. I wear long shorts or capris. I will not have long pants in my suitcase for anything. It's going to be too hot for that. The ride is farely slow, I have been told so u should not chaff too bad.
The ride is slow, but you will chaff in areas you don't want to wearing shorts. My second trip down, I brought jeans and my wife wore capris. I suppose if the shorts are long enough though, they may work. Back then, cargos were not the style.