Luis’s appartment is very well equipped, very clear, nice, and preatty huge. It is absulolutely enough for 4 person (2 couples) you have 2 bathroom, huge livingroom and big kithcen with all the stuffs you may need. I do absolutely recommend his flat, If you need any help he is more than welcome...In Portugal Uber is working very well, to get to the city centre is aprox. 10-13 eur. If u take bus to Porto you have to take Bus No. 600 (3-6 times/ hour) what is 5 mins. Walk from Luis house. The bus ticket 2€/ person and takes you to centre of Porto 20-30 mins. As far as I know you can get daily ticket, but we did not. The accomodation is 15 mins from the airport (9€ by Uber) Porto city is amazing for those who like sightseeing, you can have 1 hour boat tour on Douro for 15€ with free wine tasting included. You can walk around in the citycentre it is nice, old and beautiful 4 days should be enough for all....but those who prefer sunbathing and beach sould visit Porto During summer... In May we had only 2 nice, sunny days, and the Ocean is pretty cold yet. In my opinion Porto is not so expensive, for example you can have a nice dinner for 2 person for 25€....
Gergo