We took the Grand Tour of Panama during our 1/22/05 Galaxy cruise. (To make sure we are talking about the same tour, our tour was booked through Celebrity and included a visit to Gatun Locks, and a visit to an Indian village).
After tendering off our ship, which was anchored in Gatun Lake, our bus first stopped at the Gatun Locks. We stayed there about 45 minutes and were lucky to see two very large ships pass through the locks.
We then went to a very nice hotel somewhere in the Colon area (short bus ride from the locks) where we boarded medium size (~20 people) flat-bottom boats that took us to the Indian village. The village is located on a small island somewhere in Gatun Lake.
The Indians met our boats at the dock and directed us to a large thatched roof building where the son of the chief (the chief was ill) gave a short talk describing his village and people. After his comments, we had a question and answer session. The chief did not speak English; only Spanish and his native language so the tour guides had to translate. Very interesting discussion and he was open to any questions. After the chief’s talk, they showed us a couple native dances and asked us visitors to join in. Then we briefly roamed the rest of the village to see their homes. We spent about 45 minutes in the Indian village.
Answers to your specific questions about insects and bathrooms: Did not have any real problem with insects; may have been a few, but I cannot remember having any problems. Restrooms - - - Available at Gatun Locks, and the hotel before, and after the visit to the Indian village. Nothing but trees at the village!
The entire tour was about five hours and was very interesting and I can highly recommend it if you are at all interested in seeing different culture