Why yes, I certainly do have one that helps with all different things downtown..... I want to point out... Green (R2) and Blue (R15) follow the same route OUT of the Hotel Zone (Ave Coba) and also INTO the Hotel Zone (Ave Xcaret). They split at Ave Kabah. Only Green is represented on the map until Kabah. Make sure you do not get on the bus on the same street you got off, unless you want to go beeper downtown. Market 28 to Walmart and vise versa are very walkable from each other. I say, when you are ready to get back to your hotel, get to Walmart and get on the bus there. The waiting times under the bus numbers are way off. The R1 comes like every 30 seconds. The R2 about every 1 to 2 min. R15 is about right. R27 whenever the hell it wants too. I've waited over an hour at times. Downtown Cancun Map For a GREAT map, there is poster on the forum that sells the most amazing map sets EVER!!!! They have saved me over and over again when I first moved here. You all may have some time to order them. I got mine pretty fast... Cancun Map and Travel Guide
