During our visit to Buenos Aires we would like to go for a day trip to an Estancis and visit also the near by town. What is the best way to go:
1) Take a remise all the way?
2) Take the bus to the town and then a remise to the Estancia
3) Go with a tour company.

I know a bus will be cheaper than a remise all the way, but if the bus is a hassle or much longer, I am willing to spend an extra $50 to have a more enjoyable and longer visit.

Check the web site of the estancia and see if they can arrange transportation. Several can.

You could also get a BA travel agent who will provide the transportation and an English speaking guide for San Antonio de Areco, the estancia itself and the entire trip by car. We arranged this through WOW! Argentina and it worked out very well.

Dos Hermanos offers a car for $50 (US), split with however many passengers there are.

Estancia El Ombú <http://www.estanciaelombu.com/eombu.htm>
charges US$70 but can arrange to meet you at either airport as well as central BA.

Check out the comments about the place mentioned by the above poster:

http://tinyurl.com/3xna57

This may or may not be the kind of "estancia" you want.

By "the near by town", you probably mean San Antonio de Areco http://www.visiteareco.com/en/index.php
and this "estancia" is in another area.

My post should have said:

Check out the comments about the place mentioned by alan64: