I also posted this question (with some slight modification) on the Spain forum, but I figured that the Portugal forum might have a unique perspective on this.
My husband and I are doing a trip in November (flights are booked...so if November is a bad time, it's too late to change it) flying into Lisbon (landing on a Thursday around 8 AM) and flying out of Barcelona (flying out on Saturday over a week later). We are trying to decide what to do in the middle.
As it stands right now, we are planning to do Lisbon, Sevilla/Granada, and Barcelona. The only flights from Lisbon to Sevilla appear to be first thing Saturday morning or last thing Sunday afternoon.
He and I are both interested in spending a couple of days (or more) in Lisbon and a two-three days in Barcelona. (I have been to Barcelona before and loved it...I think he will like it a lot too). We tend to like to "settle into" places instead of running from one hotel to the next. I am worried that if we cram in Sevilla/Granada (he is dead-set on the Alhambra if we make it to southern Spain), we will end up doing Thursday afternoon and Friday in Lisbon and wishing we had more time. I also worry that we are unlikely to go back to Portugal any time soon, but much more likely to head back to Spain in the future. Should we just do Lisbon and Barcelona and supplement with daytrips?
For reference, we did a week-long trip last year to Rome and Florence...Rome was very interesting to us from a history perspective, but Florence felt like more of an "Italian experience." We liked having a bit of both.