Getting to Aguateca is not particularly difficult, if coming from Guatemala city catch a bus to Coban then a bus to Sayaxche. From there you can have a guide take you via wooden canoe, they are not dugouts. The canoes have motors, but the trip takes a few hours, the last of which is through very narrow swampland. Be prepared to dodge weeds that brush against the boat, as well as the pole that the guide uses to steer!
Aguateca has some of the best-preserved Mayan ruins in Guatemala. You will see stelae and temple ruins that may not be the largest or most imposing, but great care has been taken during excavation to preserve the area. Its location makes it half the fun--you are more likely to encounter archaeologists at work than tourists with cameras.
There are no hotels or campgrounds in Aguateca.
I got my backpack stolen on the microbus from Cruces to Sayaxche so take care