My Tho, is the capital of the Tien Giang province in Southern Vietnam. It is the first city in the Mekong Delta travellers from Ho Chi Minh City will arrive and hence a popular spot for dropping tourists on one of the many Mekong boat tours. For its closeness to Ho Chi Minh City everything is more expensive here than further inside the delta such as Vinh Long and Can Tho.
There are lots of buses daily from Mien Tay bus station in Ho Chi Minh City to My Tho. From here to the centre of town should cost 10,000 to 15,000 dong on a motorbike.
Be aware that when you ask for a ride to the city center from the bus station your motorbike taxi is likely to deliver you to Rang Dong II Hotel which is more than 2 km from the downtown area. It seems they have a business arrangement. To avoid this trap be up front with your motorbike driver about it.
The 2 Lakes in My Tho's city are nice to see, especially in the night. But other than
- the harbour where Tourists are loaded onto ships and - an nice Pagoda
there seem to be not too many spots of particular interrest. Making a longer stop over probably won't satisfy all travelers.
Homestay in Mytho From Rach Mieu you go to Unicorn Island it is on the left side of the bridge from Mytho to Bentre. It is nice homestay with hosthouse so friendly.
Since most tourists seem to arrive and leave with there "Mekong Trip" groups, there is very little (to none) infrastructure in terms of normal booking agencies with reasonable prices.
It may happen that all options out of the city are overpriced (i.e. to Chau Doc: 40$). The best solution to that would be to get back to the Bus station (approx. 3 km out of town) from where normal local busses and Futa Buslines (http://www.futabuslines.com.vn) opperate. Booking ahead might be beneficial since buses can be crowded. How ever, the website is only available in vietnamese and people don't speak much english at the phone.
So you can: a) Ask a local person to reserve a ticket for you on the phone or b) go there by Xe om / cab for 15.000 / approx 50.000 dong one day earlier and book ion advance. Its still cheaper than beeing overcharged.
Of course you can also try to get one without booking ahead.
Buses from Saigon depart during weekdays around 2:00 pm and stop at My Tho around 3:00 pm. Showing up around 2:45 pm is advisable. The price with Futa Buslines My Tho --> Chau Doc is 150.000 Dong