There is no lake between Epcot and FW. There is a bus that runs between the two (and also goes to WL); that is quickest way. You could also take monorail from Epcot to TTC and catch bus from TTC to FW (which also stops at WL but is a different bus from above). You could exit through Epcot back gate (International Gateway), walk over to Boardwalk and take bus from there to MK and then boat from MK to FW (which often also stops at WL). Note, I am not sure what your idea of fun is, but I find the less time you spend getting from one place to another the more tme you actually have to have fun at the place you are going to. The Disney transports are not my idea of fun; a monorail or boat trip can be OK but it is still just a means of getting from one place to another.
The site you refer to provides a lot of the ways to get from one place to another. It is somewhat out of date because they changed the system at FW. Also, I find most of the times listed on that site for getting from one place to another to be substantially off as it very often takes longer than what is listed there.