When you arrive there is a chance you'll be 30 minutes away from the stages. Although I have been camped by pod 9 and that is farther than BFE camp at POD 1.
Camp 84 and 85 Katrina and Billy Zane is by Pod 6 according to last years map is the farthest that you can be from the main stage. It's about a 50 minute walk.
The reason why BFE has it's name is because it's secluded from the rest of the camps.
As far as having a 45 to 50 min walk. It really doesn't seem like that long when you're with friends sharing a few beers and enjoying the festival.
If you are by yourself you can walk faster. I honestly made the 30 min walk by my self in 15 minutes.
IF you really try no where in Bonnaroo takes more than 20 minutes if you put your mind to it.
And it's not like other festivals...COUGH.ALLGOOD.COUGH where there are hills that are 40 degree angle. If anyone has been to All Good know about the two hills I'm talking about. DEATH MARCH.
Bonnaroo is all flat land. It's an easy walk and most of the time a fun one full of a beer, people watching, and sometimes a shakedown with an awesome kid with long blond dreds shooting people with a watergun.