Need Help w/ 2 week Trip April

I guess a lot depends on if you can enjoy a more hilly city by taking it slow, using taxis, etc., or of it's better for you to choose elsewhere -- there are so many places to see, no problem with that!
But what might lead me to not choose to include both those Spanish and Portuguese cities is the transport logistics--as you would most likely have to insert a flight into a two-week itinerary. I would instead add Madrid, which you could pass through by train in between BCN and Sevilla, and add some other cities in Andalucia.
But if you come across other cities that pair nicely transport-wise with BCN, then I say go for it!

Lisbon and Porto are hilly cities.

You only have two weeks. Frankly, you can't do Spain in two weeks without missing key cities.
We did Portugal a few years ago and it was a two week trip, just for Portugal.

I have been to Spain 5 times and my favorite cities are as follows:
Toledo
Seville

next tier:
Segovia
Barcelona
Granada
Bilbao
San Sebastian
Salamanca
Madrid

Do some research, find out what those cities are like. What are the key sites to see. TripAdvisor.com under things to do will assist.
You can do Seville, the Madrid/Toledo/Segovia area and Barcelona in two weeks.

Thank you! This is very helpful. Cutting out Portugal for sure.

Sevilla —> Madrid —> Valencia —> Barcelona

You get between those cities all with pretty manageable train trips. I really prefer train travel with a trip in Europe because air travel always consumes a lot of time and energy.

Madrid in my mind is an essential destination in Spain. You have to get outside the tourist bubble of the Plaza Mayor/Sol/Royal Palace area to get it, in my opinion. It’s a vibrant city with great neighborhoods, restaurants, cafes, parks and museums to rival anywhere.

The historic city center of Valencia is literally flat as a pancake. You can walk north to south or east to west across it in 30 minutes.

Good ideas so far. Not sure what you mean by Annecy as that is very far away in France. Marbella or anywhere else on Costa del Sol are not my kind of place. Be careful of Easter week as Easter is April 20 next year — very busy especially in Seville. Some people are attracted by the crowds and processions, etc, others avoid Seville at that time for the same reason. But looks like Seville’s “April fair,” also a very busy time, is in early May next year.

As a huge fan of the Costa del Sol and Valencia, of course I'll recommend those places. But seriously, if the ocean gives you joy, Malaga, Marbella and Cadiz are all excellent destinations, and all are relatively flat in the most active, historic and culturally significant areas. Madrid is great for lovers of art and fine food, though it's not one of my favorite cities. Granada is so fabulous, but not for someone who has problems with inclines, though taxis will get you to its most important site, the Alhambra.

Enjoy your trip!