You can view the Tombs from the all along the Dalyan harbour but there a couple of spots to get a really great view!
There is a simple but lovely cafe in the park, Kaunos Çay Bahçesi where you can enjoy a drink and a snack whilst admiring the amazing view. Don't forget to also look in the river as you will definitely see lots of fish and possibly a turtle or two.
Just before the park there are also small row boats, which you can use to travel to "The other side". These cost 5L per person for a return trip, normally rowed by a local women. On the other side I would highly recommend a pancake from the cafe as you step off the boat with a cold drink in the shade of their garden. Afterwards take a short walk along the road to the Kaunos ruins and you will pass a grave yard which is peaceful and offers spectacular closer views of the Tombs above.