Landing could be on a perch or deck of some kind; or if you descend far enough, the dragon auto lands and you dismount.
I would not mind something like this in Skyrim: http://www.youtube.com/watch?v=NsEA2OgC0RE
(Real time, with full control would be nice ~but... I'd be fine with a more structured flight if needs be.)
In theory it would be possible. They already managed to render the entire world in real-time for the mapsystem, it remains to be seen if that "layer" or "cell" can be edited, scaled, populated and moved in with a player hooked onto a dragon-shaped "actor".