High Speed Train station to use from Porto to Lisbon

Campanha, yes. Oriente, probably. Take Uber or a taxi in Porto to Campanha (don't bother trying to take a local train from the city center to Campanha). In Lisbon, some AP trains continue past Oriente to Santa Apolonia which may be more convenient for you. However, there can be a longish wait for a taxi at Santa Apolonia. At Oriente it's probably easier to get a taxi and you have the option of taking the metro there as well.

Thanks Chani for the info. I forgot to mention when train arrives in Lisbon , we are heading to the airport to fly back to the US. Do you think Uber, taxi or local train works better?

I think many of us would discourage you from spending your last night in Porto if you're flying back to North America from Lisbon. A lot can go wrong with that scenario, though the odds are that nothing will. I just wouldn't be willing to risk having to buy a costly, last-minute, one-way replacement ticket. Ignore these comments if your plan is to head to the Lisbon airport and spend your last night there.

Acraven...appreciate your comments, right on point...haven't decided if we are staying at the airport hotel or near a train station downtown. Actually, we haven't look at hotel options yet.

The easiest way to the airport is to take the metro from Oriente, but that may not be the best way to get to an airport hotel. If you want to spend the day in Porto and take a late train, then Uber or taxi to an airport hotel would be best. Taxis aren't expensive and Uber is less. If you want to spend the afternoon/evening in Lisbon, stay in a city hotel. Taxi/Uber from the station and another from the hotel to the aiport.