Suggestions please - traveling with 5 year old and grandma

[sbhdmh]

We will be on IOS in January traveling with our DD who will turn 5 just before the trip and my mother in her 70's. DD is very adventurous and did great with all the palaces, castles, etc on our recent Baltic cruise. Grandma is less adventurous and wants to avoid too much sun exposure. She also can't do too much walking over uneven terrain. DH and I have done 2 land tours of Mayan ruins seeing most of the major sites in Mexico. We also plan to do the Mayan Experience tour in Costa Maya. So what should we do in Belize? The combination river/ruins tour sounds good but is there a better option since we will be seeing some ruins as part of the Costa Maya tour? DH is happy to visit ruins every day and as long as she can climb and explore I assume DD would be too. Would there be any shade for grandma? Or a place for her to sit while DH and DD explore? Any and all input is welcome. Thanks in advance.