I saw "Little Big Mom" where Homer referred to Ned as "Stupid Sexy Flanders". It was slightly disturbing that Ned had a badonkadonk while wearing the ski outfit.
I can't see Ned escaping from the biodome - he'd probably get caught. He'd have to find the sinkhole instead of Maggie and accidentally leave the dome.
I don't know how I got reminded of this, but remeraber the TOH where Homer could clone himself using the magic hammock? In that story, one of the clones wound up beheading Ned.
Homer would have to take Ned to Alaska. Then he'd also have to take Rod and Todd since they can't take care of themselves. Logistically, they all couldn't fit in the car.
But then again, we could easily have the motorcycle scenes with Ned instead of Bart.