First solo trip to Portugal (June 20-29). Faro and Lisbon help?

Hey everyone! I’m heading back to Portugal this June for my first solo trip. I loved Porto and Caparica a few years ago, so I’m doing 3 days each in Faro, Porto, and Lisbon from the 20th to the 29th.

I’m not worried about the Porto leg—I’ve done São João before and I’m ready for the chaos—but I could use some help with the other two cities since I won't have a car.

Faro (June 20-23):

I really want to just chill on the beach but also see the Old Town and the street food stalls for the saints' festivals.

• Should I stay out on the beach strip (Praia de Faro) or in the city center near the Marina?

• I’m leaning toward the center so I can just hop on the ferries to the islands (Deserta/Farol) during the day and walk to dinner at night, but is the beach strip too isolated if I don't have a car?

Lisbon (June 26-29):

I’m looking for a neighborhood that’s social. I’m torn between Príncipe Real and Baixa. Which one is better for a solo traveler who wants to walk most places?

Would love any low-key food or bar spots for a solo traveler. Thanks!