Low, large tank, good suspension, all things XS650's are not. Low is not for older bikes without carving them up. The standard tank is about as large to me as would look good for the frame size, and tuned right it's good for nearly 200 miles anyway. Good suspension, change the front end to something more modern with 41mm tubes sprung and damped for your weight, and pay good money for damping adjustable rear shocks that are sprung for your weight. Don't forget top quality MODERN tires when it comes to suspension. Makes a world of difference to jump forward 30 years or so in your tire construction and design. Gearing too, if the high ball is your thing.
Nothing specific because I already have a long haul bike, but things I'd consider if I wanted an XS to be something it's not.
$0.02