I'm a personal fan of VAIS products, but this product adds little benefit to the LC. First, the iPod benefits only apply if you own an iPod and use it for video playback. Second, the LC already has composite A/V inputs. They are on the rear of the center console for the middle row. They work for the RSE (rear seat entertainment) which is already built in (so no need for the RSE video output feature). The LC already has a rear camera, so that feature doesn't apply either.
To allow playback of the RSE A/V inputs on the main nav screen, you need the Prestigious Society override (
Prestigious Society » Navigation and Video Enhancement Module) which adds numerous benefits to the LC (like the ability to dial while driving -- anything you can do while stopped). Buying a Garmin with AV outs will not let you control the garmin via the LC's touchscreen. There is no way to accomplish this without HEAVILY modifying the headunit or replacing it with another model.
If you are OK not having control up front but just want to see the maps, that's your best route. Still, I would complain to Toyota as I've heard this story before. It makes no sense that they sell vehicles with NAV in AK if the NAV is useless.