Biz Trip to PP/29Jun-4July/Accom&Tips (Phnom Penh)

Dear all expat friends in PP,
Hope this message fines you well. I have an assignment to visit travel agencies in PP,although I booked my stay at the Paragon hotel budgetly on the riverfront. I'd like to know what I should be aware of as I've been told to be careful during my visit there. I'm a small Asian woman,ok-I admit I look fragile, but not weak. It'd be kind of you to tell me where I shouldn't stroll around and during what time to what time I should avoid being alone on the dark streets? Is the Paragon hotel on the river nice? I'll have the entire morning on the 4th July free before I 'll fly back to my home in Bkk in the evening. Is it possible to do the excursion at the S-21 prison Toul Sleng in the morning and come back to the city by 2.30pm ? How muc does it cost for the remoque to get around or to the S-21? If you can suggest other nice guesthouse around Protected content preferably area around the river would be very kind of you. Also, it'd be nice to be in touch and meet other new friends living and working in PP. Have a nice day and thanks for your replies in advance.
Best -Tee