You're at that FANTASY stage of construction where, if it were me, I'd start thinking about installing a Death Star Docking Bay ring as the transition from one room to the next, so that it's the 5-footer Falcon that actually "invites" you into the next room...
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It's your room, and your house, of course. I'm just sayin' if I had a clean palette to work with, I'd think about architectural choices as reasons to build certain walls certain ways... (I also think this concept, executed well, could be it's own private recess and "dust-free" storage area for the Falcon when not on display, as you could retract it, tilt it on its side, and then have a plexiglass screen come down like a window to cover it and protect it from dust.)
But I've been fantasizing about a larger house for over a decade now... so forgive me for projecting my dreams onto your room addition!