Yes I've stayed at the Hampton. It is usually cheap except on busy weekends or when there are events on. It is the standard experience you get in European Hamptons. You can look up threads for all the Hilton properties in the Hilton forum.

Not sure if the smart card would be very useful for you. At the airport you could just buy a single ticket or a day ticket on paper, then if you really want you can get the smartcard in the city. I don't think you need to take public transport anywhere except from the airport and back, unless there are specific places you want to visit further away.

There are several people from Newcastle / Northumberland on here so unless they have something to add, the only place I can think of interest to tourists that requires public transport might be the Arbeia Roman Fort, or the beach if you really want to go to the beach. To get to the Metrocentre you have to take a train which requires a separate ticket unless you want to figure out the buses. And most likely there will be a shop in the city centre that sells the same sort of things.

You would need to be spending about 3 or more days for the smartcard to be worth it, or you intend to come back. The issue is with using up the balance. I don't have one myself so I don't know if you can top it up with exact amounts to get your balance to 0 before your final journey. As for ordering it to a hotel, that only makes sense if you will be staying elsewhere in the UK for a week beforehand.