Really, appreciate your thoughts/experiences, very helpful.Lisbon is great for a weekend away. The city is very easy to get to from the airport with the metro (or even taxi), the metro has a fixed price per trip so it cost the same going to the airport from the hotel as it is to any other part of the city (less than 2 euros). I do advise staying in a hotel near one of the metro station for this reason as all the pavement is cobblestones which makes dragging long distance with your luggage kinda annoying.
Oh, prepare for walking, wear comfy shoes. It is hilly (city of 7 hills). I don’t mind it, it let me walk off all those custard tarts that they are famous for. It also has fantastic seafood as well.
Walking not an issue, part of the reason we travel. I enjoy beaches as much as the next person (well, that's a lie, my wife does) but prefer exploring the road less travelled. And we've found meandering through the streets to a pre-set destination often delivers more rewarding experiences, sights and chance meetings. It's probably my favourite part...
Cheers, @Raymond Lin.