Lisbon is 300km or 180 miles. From Lisbon to the Algarve is about 280 km or 170 miles. Lagos is on the West side of Algarve and Tavira on the East side. From Lagos to Tavira is about 90 miles.

This is to tell you that 5 days to see Lisbon, Porto and the Algarve is perhaps possible if you are always going very fast.

I rather avoid Porto and would spend two days going to the Algarve and visiting Évora, which is a very nice town, on the way back to Lisbon.

If you need any advice about places to see in Lisbon I would be happy to help. Do not forget to see Don and Linda´s travelogues about Portugal. They are true "connaisseurs".

Best regards, João in Lisbon, Portugal