These aren't the droids you're looking for, you don't need to see his identification.
Not just in the books, but in the movie, Obi-Wan has the power to persuade minds, so why not just use it and run through like a boss? In the books, Luke actually disguises himself in his normal clothing, appearing as something else to everyone else (Crystal Star. he even lets Han see the real him, and only Han).
Sure, he might have had some strain from Force usage, but I would think that even at his age, he would have had more than enough power to last his way to the tractor control.