San Ignacio and Lamanai are at opposite ends of the country. But the cave tubing, zoo & zip lining are all in the same general spot. Easier to combine these with an overnight in SI than at Lamanai. And there are very good ruins all around SI. Or you could overnight right at Jaguar Paw where they do the activities you are interested in, or at Banana Bank or the Jungle Dome which are both very close to the same activities. SI is about 45 minutes from the zip, zoo, etc