Is one day enought to drive from Lisbon to Obidos, walk around for a bit then drive to Batalha and visit the Monastery. After visiting the monastery we would drive to Tomar and spend 2 nights at Tomar. The next day we would vist Cont of Christ in Tomar. Is the 1st dy described above doable?

Yes.

One day is enough. Obidos is worth a 2 hour visit. The Batalha monastery will take an hour at most. The best part is the unfinished cloister.

There's a free car park to the right of the Batalha monastery and there are a few picnic tables there as well.

While in Tomar visit the matchbox museum (free). It has about 40,000 matchboxes. It's right by one of the free parking lots, a few blocks from the TI.

Obidos, two hours at most. Make sure you tour the church, west side of the main street with beautiful interior tile work. Filled with tourists,one of those towns that today exist only for the tourist trade.
Then , Alcobaca is much more interesting than Bathalha.The church is beautiful, simple design.The tombs of Pedro and his beloved Ines complete the day there. If you have time, have a seafood lunch at Nazare.

Loved Alcobaca - the church really is magnificent. +1 on Nazare as well - terrific seafood and so cheap!

Not much to see in Tomar, unless you have specific reasons for going. Town center is nice (scenic) and there is shopping and a few restaurants/cafes. A visit to Convento de Christo is a good idea. The architechture is beautiful with some stones having turned an orange color. I found the long halls with rooms for the monks very interesting.

Other than that Tomar was not as impressive as Obidos, with its walled in town center and stunning white-washed buildings trimmed in bright blue, yellow, etc. We walked completely around on the ramparts. There are stairs to the left when you enter thru the portal - DON'T forget your camera!! Nice shops & restaurants, but during summer the flies are relentless!

But, by far the most impressive trip north of lisbon is SINTRA!!!!!! We took the rail train there and then the bus up into the mountains. The 19th cent. palace of the Portugese royal family is like a fairy-tale! It sits on a mountain peak and will transport you to another place and time! And Castelo dos Mouros took my breath away. It's like a miniature Great Wall of China, built in the 9th century by the Moors. You can walk the ramparts but: watch your step and hold on in high winds (not for those with acrophobia)! Most sweeping panaramic views, a camera is a must! And if you eat at a restaurant in the small village of sintra, ask the locals where they eat. The eateries on the main road were a bit too touristy of us, so we ate at a "mom & pop" place off the beaten path (yes, mom really does the cooking). We dont speak portugese & they didnt speak english but it was one of the most authentic expeiences during the entire trip! Have fun!