answered about 4 months ago by grubby
1) I don't know of any detailed maps with all the minor roads, but you can get a reasonable vietnam map with provincial detail at any of the bookshops on Trang Tien I think.
2) Tram Ton Pass, and the windy descent towards Lai Chau, Hoang Su Phi in Ha Giang (much of Ha Giang is wild and beautiful)...
Actually, all of it. Everything apart from the larger towns is worth seeing, but be prepared to get lost. With 4 days you have time to loop from Sapa back to Hanoi through the North East or North West.
3) get your bike checked out before you go and take a few spare parts with you.
HTH
