Coming into Bangkok for a week and would like to do a tour of the city on Chao Phraya.  Would like to get off and on at different locations if that is possible.  Are there companies to stay away from or is it not even worth it?

Just use the regular Chao Phraya Express boats..the old ones are 15 THB, the brand new ones are 30.  The clowns will try and sell you a book of ten trips for 200..but it is better to just buy individual tickets or pay on the boat.  Try to make it so you are going against rush hour.  Also, there is a connecting walkway to the mrt blue at Bang Pho, and it is also very accessible to KSR...no need to base your trip from Sathorn, unless you are staying there.  I live by the Nonthaburi Pier, also called Talad Non.  Great photos around sunset.