I just went through this process. I left my truck in storage in Costa Rica while I flew away for 2.5 months.
here is what I have learned...
In theory, you should be leaving your vehicle in "government" approved storage area - there is one right next to the airport.
The idea is that will prove that you are not selling your vehicle and leaving without it. Also, by doing that you can change the status to "Suspended" and when you come back you restart the permit so you don't loose any of your 90 precious days.
When I put my truck in storage, the clerk made a mistake and changed the status to "Canceled" instead of "Suspended". When I got back, it took me 2 days to sort out the whole thing and it was extremely frustrating.
You can read more details here:
Panamericruiser - An Overland Journey through the Americas - Stage 1 - Page 12 - Expedition Portal Forum
Also, to my surprise they did not check anything at the airport when I left - the custom guy did not even had a computer or put a stamp in my passport. They did not put a stamp like in Panama for the vehicle either.
So if I were to do it again, i would just left the car at a friend's place or in hotel, unless you really need to preserve all of these 90 days.
But in your case, if you leave for a year you will have a problem because the 90 days will be passed.
let me know if you need more details
Last edited by 2aroundtheworld; 11 Apr 2011 at 17:41.