Hue - vietnam

Flying to Hue this afternoon. I have three quick questions:

1. A few travelers told me that a nice day trip is to rent bikes for the day and bike out to Thuan An beach. The rough guide says the beach is dirty. Anyone done this recently and could recc this trip or is there a different beach that is not listed in the rough guide? Also, haven't rented bikes yet in vietnam. About how much should I pay for a day's rental?

2. Beach parties in Hue? True? They sound fun, how do we know about them?

3. What is the best way to see the mausoleums along the perfume river? Can anyone recc a guide or tour agency they went with? What was the average cost for the trip?

Thanks A Bunch!