I did some hiking and repelling @ Dalat.. was pretty fun. Did a 4 story jump into the river.
Then it's the usual few.
Hang Na's crazy house ... feels a bit of a ripoff of Gaudi architecture.
The lake, the waterfall, market... etc... All can be found on the usual websites. Depends on what you want to do. I personally preferred Sapa much more than Dalat.
Get a motorbike to move around, it's worth it. Traffic is easy.
Some places to visit in Da Lat. If you have the time, I would visit Hue and Hoi An (UNESCO World Heritage Site).
Hang Nga "The Crazy House"
This is a very strange guesthouse which was built in the style of the Spanish artist Antonio Gaudi. About 20 years ago Mrs Dang Viet Nga, an architect who studied in Moscow for 14 years, purchased the property and set about the redesign and construction of this weird guesthouse with its caves, giant spider webs,, scary looking animals, unusual rooms and winding stairs.
Da Lat Railway Station
This railway operated from 1928 to 1964 when it was closed due to the war. It now operates mainly as a tourist train which operates over an 8km length of track to Trai Mat village. The trip takes 30 minutes and during peak tourist season there are 6 trips each day, however not as often during low season.
Lat People Village
The Lat People were the original inhabitants of the Da Lat plateau and in 1893 when it was discovered by Dr Alexandre Yersin the Lat people totalled several hundred. The Lat ethnic minority together with other local hill tribes have a population of 5,000; the Da Lat district population being approximately 200, 000.
alternatively you could engage the services of the dalat easy riders. i did that last year and it was really cool. motorcyclists would ride you down the rural areas of vietnam to beautiful places. your rider will be like your personal tour guide and will bring you around/ explain things to you.
depending on your budget and amount of time you have, you can even ride back to ho chi minh. plenty of amazing photo opportunities along the way.