Looking for tips/fellow traveler - North of Vietnam

My friend & I did SaPa by bus from Hanoi last April. The trip was very comfortable and pleasant. We made resevations a day in advance and extended our stay while in SaPa and changed the return date on the ticket with ease by phone.  There were several stops along the way for food and restroom breaks although one of the restroom stops featured gender separation for standing or squatting in the wild---the ladies may have had a tent. Sounds odd but really wasn't a big deal at all. The bus company was just a block down the street from the Hanoi Merci Hotel on Ly Thai To Street which was my base station while in Hanoi. It was very conveniently located within walking distance to Hoan Kiem Lake and the Old Quarter in one direction; and the Hanoi Opera House, The Metropole, museums and retail in the other direction. While in SaPa, I was quite happy with the SaPa Panorama Hotel in a 5th floor room with a mountain view toward the downtown area. It was easy to reach by foot from the bus station. Be prepared to be swarmed by locals as you step off the bus who seek to sell their crafts. Having a friendly attitude helps but firmness was sometimes needed too. The city discourages tourists from purchasing from them. We actually befriended Sasha & Bao who walked us to the hotel from the bus and two days later escorted us on a very fun tour of their villages.  I must point out that there are many other hotel selections near either the Merci in Hanoi or the Panorama in SaPa that may fit your travel style better. As always, just do your due diligence. Rented scooters to travel about 30-35 km to Silver Falls which was a very scenic ride. Go early in the morning when it is clear. Good luck. I'm certain you will enjoy the experiences.

Hi Solene,
Pleased to give you some of my advices about your trip. As I know, August is not the best time for you to visit Tam Coc. The best time for Tam Coc was in the May and June, so it will be better if you choose the another destination. Mai Chau is amazing almost time, because the feature of Mai Chau is mainly about culture such as local food, ethnic minorities, green space and fresh air. Don't forget to bring out the raincoat or umbrella because it is rainny season now. Spending 3-4 days traveling in both of them is enough.
I traveled in Sapa 2 times and I think the end of August and the beginning of September are the perfect time to see the mountainous landscape and terraced fields. Or you can go around and visit famous destinations and village of ethnic minorities, maybe with surcharge or not. Drinking coffee in the cafe in downtown Sapa is also a good experience. You can go to Sapa directly by bus, or you can go to Lao Cai by train and then catch a bus to Sapa. Spending about 2-3days in Sapa is fine.
If you have any questions, you can ask me everytime. I am willing to help you out.

Wow thank you! That was very useful !
Do you know any other places worth the travel?

Dear Solene,
Beside of Sapa, you should consider Tam Dao for the trip at the end of August I think. Tam Dao is beautiful and green almost time and the climate there is quite cool, like in Da Lat and Sapa. You can walk around to Ancient Stone Church,  Sky Gate, Truc Lam Tay Thien monastery, Sliver waterfall. You can sightsee from chamber of cable car. I believe in that the landscape there is amazing. Go trekking can also be the another choice instead of using cable car.
In Tam Dao you can try famous special local food such as stir fried chayote tops, grilled chicken, grilled pork and grilled eggs. About commuting, it takes you about 2 hours to get there by bus or motorbike from Hanoi. I think you just need 1-2 days to visit all of Tam Dao. The road is sometimes winding, but interesting.
Ha Giang is also a beautiful destination. The landscape is wild but spectacular. The road to get there is awesome I promise. But it is better if you travel there in September or October instead of August, though August is fine. But it almost takes you about half a day to get there from Hanoi. So, I think 1 week is not enough for you to visit all of these destinations, because you have to spend at least 4 days only in Ha Giang, including commuting time.
I hope I can help you with these advices. ^ ^