What vehicle would you pick for my (rather short) roleplaying character?

Try a BMW /2 frame with later /6 engine. A few short ladies have them at shafty rallies, the low contour frame allows a very low seat. /2 frame is reinforced from factory for sidecars and the rear of loop frame can have a trailer hitch easy-again some seen at rallies. Or go the old pre 1957 harley frames. Maybe a WLA cycle- Army pattern WW2 and Korea- that has low seat frame and often had tommy gun or carbine scabbard attached to front forks..