We used a number of ways to get around Bangkok. Taking a train down to the waterfront was a nice way to see the inner parts of the city. The main idea was to get down to the ferry system.
The Chao Phraya River has a number of attractions right along the river bank. Using the ferry system I found was the best way to see Bangkok from a bit of a distance. The various temples stand out.
The ferry system is very much like a hop on hop off type of tourist bus system. The cost is minimal, but you have to learn the various types of ferries. You can hop onto to a direct ferry that may not stop at the various stops you were hoping for. The ferries do fly the various flags that give you a sense where they might be going and if they are coming for you.
We waited at one stop for a particularly long time till we decided to take another ferry across the river to access a more central ferry depot. Don’t hesitate to experiment. Its only a river.
We found this to be a great way to access the main temples we were interested in.