Avis and the Nav System

[Vanelil]

Hi, I have a quick question. My wife and I are heading to Disney in January. We are renting from avis, and they have an optional nav system you can rent for $10.00 a day. We are both navigationally challenged, so I was wondering is the nav worth it?
If you have used it is it easy to use? Lastly are all the Disney destinations programmed into the nav alrady or would I have to do it? Im sorry my one question morphed into three.
Thanks to all these forums are great!

 

[CarolA]

I have not used the Avis version only the Hertz.

Not all Disney destinations were in it. They kind of lump the theme parks into one big area which I think actually was going to lead me to DTD. I think a lot of the hotels were in it.