Hello Steve.
I have time in hot-and-high and on dirt on both long- and short-nosed 310's. You specifically ask about the gear: Yes, looks a bit spindly, doesn't it? But I went into countless bush-strips with 310's and boy did the gear take a clobbering! Never had a problem, even the time when I went sideways for a bit due to a landing on a muddy strip. The maintenance costs of the undercarriage are relatively high, though. (but as an ex-owner you will know this)
While I cannot recall specific numbers we never had runway-length issues, even before the VG kit hit the shelves. These days all 310's seem to have them fitted anyway, and they do make a difference. Heating never works well. Doorseals usually let go fairly soon. Hardly ever saw a properly functioning autopilot. The short-nose will have weight-and-balance issues if you try to load 5 pax and any amount of fuel. A friend came home on one engine in a short-nose, 4 pax, maintained at around 7000' if I recall correctly. Lovely aircraft, fast and rugged, though I don't envy you your AVGAS-bills! Where will you be flying it?