I suspect the Hop On Hop Off Bus isn't going to be worth the cost if it's too cold to sit upstairs.

I suspect the Hop On Hop Off Bus isn't going to be worth the cost if it's too cold to sit upstairs. Is a 3-day Barcelona Travel Card worth getting? Or should I get a T-10 ticket and walk a lot instead?
I will be going to watch Flamenco at Poble Espanyol discount cruise vacation package one evening (have already paid for it). Will it be easy to get a taxi back to the hotel after? I'd rather not take a bus or the tube that late, especially in the dark. What should the taxi cost, from Poble Espanyol to Las Ramblas, at night?
From what I have heard there are elevators going up the towers at La Sagrada Familia. Then people are supposed to walk down. So, are the stairs inside the towers (where it's hopefully nice and warm) or are they open to the cold and wind?
Will I get sick of Gaudi if I visit both Casa Battlo and La Pedrera on the same day? They seem to be located very close to each other and it should theoretically be a good idea to do them at the same time, maybe with a quick lunch in between. But I'm slightly worried that they will be too much alike and I won't remember which of them I saw what in.
There is a big difference, IMO, between Casa Battlo and La Pedrera, so I agree with Danon. Definitely visit both on the same day since they are diagonally across the street from each other. Make sure you go inside both of them. You miss out on a lot if you just look at them from the outside.I thought renting the audio guides was worth the money because you have a better understanding of what you are looking at. Casa Battlo is my favorite, but the roof of La Pedrera is amazing.
I can recommend Catalana Cerveseria for a restaurant. It's located in Eixample, on Mallorca St., I think. Food is delicious reasonably priced. You can click on my name to read my trip report from October 2010, if you like.
It's easier to take city bus 24 from Catalunya or anywhere along Passeig de Gr cia to the side entrance of Parc G ell where the bus stop is right next to it. No climb whatsoever necessary, except for what you want to do inside the park.
I doubt that it will be a problem to get one. Worst case scenario would be to take the regular city bus from right outside the entrance to Universidad and walk from there to Rambles (not knowing on which part you will be staying)
The cable cars at Montjuic are enclosed so should be OK. The top cars are more modern and hold 6 or 8 people, whilst the large cable car down to the port holds around 20 people. The windows are open in the summer but close when it's running in the winter. Be aware that you have to walk between the two systems, which takes 5 or 10 minutes.