Any suggestions for traveling from Lagos to Porto would be appreciated. We plan on doing this during our third week in Portugal and prefer not to make many stops along the way. We will be traveling with another couple and refer renting a flat for ours days in Porto. Our first week will be spend in Lisbon and second week in Lagos.

I would get up early and take the 06:14 train, which will only require one change. Otherwise you could take the bus to Faro or Lisbon and fly, but the train will be faster. See train schedules at bahn.de.

The train is the only way to go! There is a train at 9h00 and another at 12h53 that take less then 8 hours.

Train schedules can be perfectly understood from the actual website for trains in Portugal.
https://www.cp.pt/passageiros/en/
No need to use a German website.

Of course they can, but bahn.de is good to know about since it covers the whole of Europe.

Thanks for your imput...train it is. However can anyone suggest a town we should stop in for the night in case we decide to not go straight to Porto?

Coimbra. Don t miss the library, or the Roman remains at Conimbriga.