spain-portugal

Malaga, Sevilla, and Madrid are linked by the high speed AVE train, which makes it very easy and comfortable to visit the three in a short time. Lisbon is the outlier; you will use up a significant portion of your 6 days getting there and back, even if you fly. There is more than enough to see in Sevilla and Madrid, especially if you add a daytrip to Toledo from Madrid, or a hill town from Sevilla. Or add Granada and do a triangle by train, Malaga to Sevilla to Granada, up to Madrid and back to Malaga on the AVE.

'We'll be in Malaga, Spain for a motorcycle tour. ' - You will tour by motorcycle? Whatever your transport, as already advised, you will expend a great deal of time travelling and very little time in the destinations on your wish list, if only six days. Logically Lisbon should be left out. Seville to Madrid and return, unless by train or flight will take up one to two days.
Think again, unless you just like modes of transport.

Thanks for the input, Our motorcycle tour of 8 days is prior to the 6 - 7 days after when we are on our own. Thanks again

I just noticed you said "southern Spain.". How about Sevilla, Cordoba and Granada?

Which is it?
'we want to travel within southern Spain and Portugal.' or 'we want to visit Lisbon , Madrid and Seville' As you have not volunteered where this motorcycle tour from Malaga is taking you, my answer to your original post still stands.

I agree with the others that it is hard to advise not knowing much about your previous plans. And also that Lisbon is a bit far to squeeze in with the others in only 6 days. That's only 2 days each city, including transport. Even though the travel between each city is only a few hours (if flying to/from Lisbon), it takes another couple hours to get to your hotel, settle in and get familiar with the area. So that only leaves about 1 day to see each city. And each one you list needs 2-3 days to do it justice. I recommend editing your itinerary to leave at least 2-3 days in each place, not including travel time. Madrid for example, has so many daytrip opportunities that staying there 4-5 days is not unreasonable.