Which Lisbon station to Lagos?

Hi, I searched the forum here and it looks like the topic of "train from Lisbon to Lagos" has been discussed several times already. However I can't find the answers I am looking for. In August we'll be visiting Lisbon and will be staying at an apartment near Cais do Sodré. Following Lisbon we will be taking the train to Lagos. Using www.cp.pt, it looks like I can take the train from Oriente, Entrecampos, Sete Rios, Santa Apolónia or Cais do Sodré. However Cais do Sodré and Santa Apolónia are not very desirable in our situation because we are traveling with large luggage and these stations involve extra train changes. I guess we won't be considering Oriente either since it's way out by the airport. So that leaves Entrecampos & Sete Rios as options. My questions are: 1. We are planning to catch the train that departs from Oriente at 10h02. Which station (Entrecampos or Sete Rios) should we go to, that's easier to navigate? 2. How much time via taxi will it take for us to get to the train station from our apartment near Cais do Sodré? 3. How much time ahead should we get to the station to allow for security check? Any help will be greatly appreciated