Seems to me he did, especially if he bought the Coke beforehand in order to use it as a prop all the way, if necessary.
Carrying the already-opened Coke, get to the Second Floor Lunch Room and hang out there, expecting to be encountered ("No, I didn't hear any shots," or "I work here"), when they leave, walk through Mrs. Reid's office to its front door and exit through it, walk down the wooden steps to the front floor, maybe hang out in the "lobby" for a few seconds, then walk to the rear of the building and exit it through the loading dock door.
Instead of looking suspicious by immediately walking or running away from the building, walk along the side of the building towards the front (as alleged by B. W. F.), cross over to the other side of the street, ... and, well, "take it from there".
-- MWT 
LHO tried to blend in with others as best he could. But I don't believe that he had a well-planned escape figured out very much ahead of time. It might be coincidence, but then again perhaps not, that he fired three shots (he was reportedly fascinated with the number three) and then had one shot left in the rifle to potentially shoot anyone who tried to stop him while he was still on the sixth floor. He was smart enough to ditch the rifle when he did so he wouldn't become an obvious target for armed law enforcement officers (who were plentiful all around the TSBD). We have the reports of witnesses who testified that they saw LHO leaving the TSBD and on the bus, cab, rooming house, Tippit murder scene, leaving the Tippit murder scene, shoe store entrance, and the Texas Theater. Tippit most likely noticed something about LHO that drew his attention to him. I think that it could have simply been a hurried pace, or maybe even that LHO saw the cab parked on the corner of Patton and 10th and raised his hand in an attempt to hail a cab. If he did, and Tippit mistakenly thought LHO was trying to get
his attention, that might also explain why Tippit pulled over to the curb. I don't see any obvious escape plan in his reported behavior after the JFK shooting. Going to his room, apparently to get the pistol, is the only act that appears to me might have been planned ahead of time. And even that act wouldn't have been necessary if he had truly well-planned an escape far enough ahead of time. So to answer your question, no I do not believe that he planned an escape very well at all.
