I like the Sport 22s... like an old-school Airstream (small frontal area, simple/practical layout and systems.)
Be sure to take plenty of propane to Big Bend, nights in March are likely to be chilly out there!
SA's current weather (short, fairly light freezes) should let you get away with halfway winterizing. A little bit of water in the traps and such wouldn't likely cause a problem as long as you don't have much water in the pump and in fixture valves you'll be fine. If it's parked somewhere that you can keep a little space heater on low (both temperature and wattage) you'll probably keep everything above freezing in the first place.
Il Carriaggio ó 1975 Argosy 24 | Il Progetto ó 1976 Argosy 28 Center Bath | WBCCI# 15566
He has all of the virtues I dislike and none of the vices I admire. ó Sir Winston Churchill