Like many(?) fans of ASOIAF, I've a silly fondness for "Rickeen" - the concept of a post-War for the Dawn teen Rickon Stark, raised in Skagos by Osha & half a wolf because of so frequently warging with Shaggydog, deciding to steal himself the bookish, Southron Princess "Shireen" because she's kind and has been teaching him how to Lord. Hijinks ensue.
PRACTICALLY speaking, of course, is the very real Powerhouse that their marriage would create: Shireen is the Princess of Dragonstone, the legal heir to the Iron Throne (by right of Baratheon conquest & her NOT being a bastard) and, with the demise of Renly Baratheon, Heir Apparent to the Stormlands; Rickon is Heir Apparent of The North (Robb's Will notwithstanding) and, by right of his being male & able-bodied, the rightful Lord of Winterfell. That Rickon's been AWOL with Osha, presumably learning the ways of the freefolk & speaking The Old Tongue, conveniently sets him up for acceptance from both the Great Northern Houses (your Manderlys and Umbers and Mormonts) AND all the freefolk settling in The New Gift.
But what is the state of things for this ship, as set up in canon?
Lord Davos Seaworth, smuggler extraordinaire & Hand to King Stannis, has been sent by Lord Wyman Manderly (leader & head-schemer for a good third of the many Conspiracies Great & Northern) to fetch 5-year old Rickon from Skagos, an island just off the coast from Eastwatch, south of Hardhome, and known for cannibalistic wildlings & deadly unicorns.
Meanwhile, at Castle Black, Princess Shireen is presumably in the King's Tower & thus "guarded" from the ongoing mutiny by Wun-Wun the Giant. Shireen is, at this point in the story, 11 years old & is good friends with Devan Seaworth (13), eldest surviving son of the Onion Knight and thusly his heir, and her double-cousin Edric Storm (13, Robert's bastard by a lady Florent, currently secreted away in the Free Cities & out of the reach of Melissandre's arsony).
Had Queen Selyse not pitched fuss over which derelict castle at The Wall would best befit her station (she HAD wanted the Nightfort but, uh, Castle Black was safer & less haunted), she and her court (Shireen included) would still be at Eastwatch. Lord Davos set out for Skagos from White Harbour & Eastwatch is the closest friendly port from Skagos, and it's very plausible that Lord Manderly had this in mind when charging our Onion Knight with his fetchquest: a betrothal agreement, between Rickon & Shireen would secure a degree of King Robb's legacy, give Stannis a kingdom (the Stormlands currently warring against itself & the Golden Company of "Aegon VI"), and afford to both children some obligatory protection from harm through their respective factions.
As it stands, it's unlikely that 5-year old Rickon will be leading an army of Skagosi unicorns to hassle mutineers, Freys, and Boltons from atop his direwolf, & unlikelier that little Shireen would safely walk amongst freefolk with the scars of [her surviving] Grey Scale so obviously on her face. I do think they'd find each other fascinating, if introduced, but babysitting one's betrothed during an apocalypse is a scenario unlikely to be long-lived should it occur in Winds.
