Building Bubbles a distinctive bicycle would be a good business move, AND good for Bubbles emotionally.
Even if a relatively ordinary bike could support her, a large-frame good-looking bike with 30-inch Coker tires would be unusual enough (and on it she'd be non-threatening enough) that people would walk up to her to ask where she got it or who made it -- and then she could hand them a business card.
This is from experience, BTW. As a huge guy, when I'm walking around I often see people crossing to the other side of the street to avoid me, shying away, taking defensive postures, putting their heads down, etc... fear reactions that I'm SURE are part of Bubbles' alienation from the world. When I'm riding a bicycle though, nobody acts scared of me. It's like night and day.
Assuming that Bubbles weighs only ~180 kilos or ~400 pounds means assuming that she only weighs what a human her size would weigh, IE that she'd have approx. neutral buoyancy in water. To weigh ~130 kilos or ~300 pounds, at her height of about 2.2 meters, even a human would be skinny, and she's not. But military vehicles average about twice to three times the mass of civilian vehicles the same size, so I wouldn't take odds on her chassis mass being proportional to human mass, even for the same size.