At least 4 months and then another 4-6 weeks for a MY12 just because of navigation? I do not buy it... The hold on navigation was lifted back in mid-September with normal scheduling and production resuming at the beginning of October. Now the wait times may be a little longer compared to other vehicles, but that is simply due to demand.
The other thing is they will not even be building MY12's in 4 months and you could have a MY13 with navigation before your summer road trip. The MY13 order bank is scheduled to open this coming Monday, 11/14/11, and production is scheduled to begin on 02/06/12.