We have't put in raised beds, but have started to plot them out. So we have plots and mulch path ways in between to walk on. We haven't decided if we will build the raised beds yet or just keep the plots. We have a pretty big garden and the raised beds may not be cost effective to build! 
My DH wants to try to grow potatoes in tires, sounds neat, all you do is lay a tire down, fill with dirt. When the potatoes sprout, place another tire on top and fill with dirt, you stack them 3 or 4 high. When ready to harvest all you do is knock down the tires! No more hacking up the taters with the pitch fork!
They say tomatoes do well in the tires as well as peppers. 
People are always throwing their old tires on our property, so we might as well  put them to a good use!
I wonder how red necked the tire garden will look! LOL!!
      Brenda