Vietnam forum

We're planning a 3 week trip to Vietnam in late July.
We arrive into Saigon and are thinking of hiring motorbikes and heading to Can Tho and exploring a little of the Delta on the way.
Not too much of it, just basically drive to Can Tho and make a few small excursions and stops on the way. We were thinking
- One day travel there
- A day exploring/motorbiking around the countryside
- A day's travel back to Saigon

Is that too short? It's just we want to fly up to Hanoi as soon as we get back and work our way slowly down the coast. Doing that is the priority, so if doing a little Delta trip is going to need more than three days then we'll probably just head straight up North.

The other option is heading straight up north and taking a few days to do a motorbiking trip out of Hanoi. Would that be a better option?

Thanks for your help.