We stayed at Mopan River Resort in January and loved it so much that we plan to go back next year.
They only go to Tikal on Tuesdays and Fridays. You'll leave the resort at 7:00am and return at about 5:30pm so it's a full day with no opportunity for other activities. Tikal is a powerful experience and should not be missed! I think if I was that close that I would do an independent trip if I couldn't get on the resort tour.
We went to Xunantunich on a Wednesday but, because it's so close to the resort, I think they go every other day. It's a morning only so you'll have time to explore Benque or kayak down the river in the afternoon. Xunantunich is the first Mayan ruin that we have ever seen and I was, and still am, totally in awe of it.
We were only there for 4 days and the Cahal Pech trip was not offered during our stay. When we go back next year, we are going to be sure to allow time for it as I hear that it is spectacular. It is another of their 1/2 day tours so again there will be time for another activity in the afternoon.
For all the land tours, I wore cargo style shorts with lots of pockets for the camera, wallet, etc. Many people had backpacks or waist packs but I found mine too hot. You need a good wide brimmed hat (if you find a nice white nylon one there, it's mine...I lost it!) and loose shirts with at least short sleeves. I saw some blazing sunburns on people wearing tank or 'strap shoulder' tops. I wore good 'wicking' socks and excellent running style shoes for traction and was glad I did. Some people in sandals had trouble climbing the ruins.
We didn't see any bugs...none...even at dusk on the river! Maybe we just lucked out. I wore a 45 sunscreen all over my pasty body and I still got some colour through it...the sun is strong! Respect it if you want to enjoy your vacation.
I know you'll have an excellent experience at Mopan River regardless of the activities you're offered. Say hi to Pam, Jay and Alexi (if you are lucky enough to have him for your tours) from Cath and Dan.