best way to refinish trunk exterior

Do not sand. Use stripper. The stripper that does not have to be neutralized later is easiest to use. Read the instruction and work in well ventilated place. Taking time, using soft scrapers such as plastic and brass brush, and removing by multiple tries will get you to bare wood. Peel off stripper is effective but not worth the price in your case.

Sanding the bare result is your judgement. If you decide that some spots have to be repaired by sanding, don't like the original stain, etc, you will have to sand the whole thing, but the result is usually worse than keeping the original. Your wife will be deciding, of course.

Do you know the history of that trunk? Do you know for certain it is not old enough to be an antique? I would take it to an antique dealer and get it appraised before I did anything to it.....mold and all. You would be surprised that what people consider junk is often antique quality. Trust me, I have been collecting antiques for several years and I still get surprised by what I find. Any dates or names on this trunk?