Regarding the Navigation, from what I have read here you may not even want to use it once you get it. I use Google maps on my phone which is "live" and it gives you route updates based on traffic so if a faster route becomes available, it will let you know. From what I have read here, the Ford Navigation is pretty bad.
Regarding the MP3 files, I just use the Bluetooth connection on my phone to play my music. You launch your music player or online music service (Google Play for me) on the phone and then you use the car controls to adjust volume or to skip forwards or backwards. You can't search for music through the car and still need to change Genres and such on the phone but for sound quality, this is a big advantage. The SEL sound system is pretty disappointing so if you use a USB stick or basic MP3 player, you are stuck with the basic Bass, Mid and Treble controls of the car. Using my phone, I have a program called Viper Audio http://vipersaudio.com/blog/ which dramatically improves the sound. It has a 10 band equalizer along with other options like Viper Base which can make it sound like you have a subwoofer when you really don't. It really is an amazing app. It isn't just a base booster but does some amazing sound processing to even make ear buds sound like there is a subwoofer without any distortion or over driving of the speakers. The point isn't to get people to install this app since not everyone will be able to but to point out that using the phone instead of a USB stick or basic MP3 player can give you much improved sound quality.
The stock speaker are some of the cheapest I have seen. Below are some pictures showing the stock front speakers vs the Infinity 682.11cf Kappa speakers that I installed. The rear speakers are the basic Ford speakers that does not have a separate tweeter and looked Identical to the speakers I took out of my 1999 F350.
I don't want to sidetrack your thread and if you like how the stock system sounds then use a USB stick or Ipod and be happy.
Oh and you are getting a CPO (Certified Pre Owned) vehicle not CAP.You can't go off the website as far as what version MFT it is running. If the previous owner never updated the website or ran a Vehicle Health Report, it will not show what version is actually running in the vehicle. Once I ran the Vehicle Health Report, it updated the website and now shows the current version. It was showing the version when the car was first sold previously to that.
I hope you enjoy it once you pick it up! I love mine with the exception of the sound system which I am working on.