2. with white sands/You can see/Viet Nam's prettiest beaches/tropical rainforests/some of/and/.

You can see some of VN's prettiest beaches with white sands and tropical rainforests.

3. Sa Pa/It's best/Many visitors/during the rainy season/report that/to visit/.

Many visitors report that it's best to visit SP during the rainy season

4. excellent/fresh seafood/an/place/This is/to enjoy/.

This is an exellent place to enjoy fresh seafood

5. a camera/You mustn't forget/rice paddies/to take/of the/wonderful pictures/.

You mustn't forget a camera to take wonderful pictures of the rice paddies 

6. and/there/Tourists/fishing villages/can visit/national parks

Tourists can visit fishing villages and national parks there