Thank you all again for the elaborate replies.
I was aware that 3 days might be too much for just sightseeing - my plans include a good amount of time at the hotel pool as well (and yes, I know there are nicer places for pool/ beach holidays
)
River cruise and museum sound nice, I might give the markets a miss - I'm currently working in Asia and I guess Phnom Penh markets won't be much different to others in regards to fakes, offers, hawkers, and invasive sellers...
Travelling alone, I don't think I'll eat out anyway, but rely on hawkers and, oh well, the club lounge.
Maybe I'll head to Oudong for half a day or so.
Thank you again!