The only river boat that Iknow of is a trip down the Kok river from Thaton to Chiang rai and it looks like fun, but are there any other river trips of any length in other areas of Thailand??

Chao Praya in BKK.....how far can you go up or down river??

An overnight trip would be fun, but don't think so in LOS.

Any trip reports??

I know this doesn't answer your question, since I don't know of any other riverboat trips in Thailand either, but there are some great trips in neighboring countries. Myanmar has several, but I'm partial to the trip down the Nam Ou from Muang Khua to Nong Khiaw in Laos.

Regular express boat goes from TaksinBridge up to Nonthaburi,short trip will take you to Banglampu;it is very nice trip,fun and available until sunset.

I think,there are river boat cruises up to Ayuthaya.

In Kanchanaburi - you can stay in houseboats.

Technicaly - it is not Thailand,one side only,you are in Laos:go to Chiang Kong,cross Mekhong - from Lao side(Hua Xai) you can take boats down the river or up,

All sort of comfort and speed is available,slow,very basic and cheap(2 days to LuangPrabang),also slow but not basic,much more expensive and very expensive,delux style with accomodation,

also - very fast speedboats,no comfort,but quick.

There is another option - take boat to China from Thailand,information is on TV,easy to find.

In Asia - Rocket Steamer from Dhaka to Khulna in Bangladesh is worth of your trouble.