Valencia and Murcia are not in Ricks book on Spain??

A common criticism is that Rick's books omit places. This is true, but that's a feature, not a bug. The books are not meant to be comprehensive, but as a suggestion for the top (most popular) places for visitors, especially those who have limited time (as most North Americans do - infamous for too-short vacations).

Spain is a big, diverse country with plenty to see, and many places not covered in guide books. That's OK.

What are your plans so far? I have been to Valencia. I will admit I was at the end of a 3 week trip and travel weary, so it wasn't a wow city for me, but it is different from, say, Granada.
I tend to be practical and stick to cities in a regional area. If uyou are visiting Madrid and Barcelona, then Valencia is practical. There is a bus from Valencia that will even drop you off at the BCN airport.

I’ve visited both and can’t say I was impressed with either. They are worth visiting for a day, but didn’t have any memorable sights to visit. I can’t see myself going back to either.

Like Italy, there's more not covered than is covered. Michelin Green books are helpful to cover areas not covered in RS.

My best memories in Spain are Holy Thursday processions in Zaragosa and April Fair in Seville.

I want to go to Valencia during their fire festival. I probably won't go any other time because then I won't make it back for their main festival.

For me Murcia is too close to the dreaded (by me) Costa del Sol. I have an aversion to golf course/condo resort communities so I don't go anywhere close to that area. It's a personal phobia in the sense of being, at least somewhat, irrational.

For me, the greatest coast is Costa de la Luz (essentially Tarifa to the Portuguese border) because it's miles and miles of undeveloped beaches - heaven for me. There are a few cites but also long stretches with just enough civilization to meet your basic need for food and lodging.

The northwest is also appealing because it's Gaelic and much less visited than the main tourist capitals of Spain (Barcelona, Madrid, Cordoba, Seville, Granada and Toledo). The language is Gallego and the music is bagpipes.

The basque coast is a little too popular, for me, in summer and a little too cold the rest of the year but certainly worth visiting.

The cities I consider "classic" Spain are Burgos, Valladolid, Zamora and Salamanca. The huge castles (La Mota, Coca and Penefiel) and old centers are chock full of history. Valladolid is known for their Semana Santa celebrations (but not internationally known like Seville), plan for it and see the best of Spain without the tourist crowds.

My favorite castles outside Castillo de Leon are Olite and Belmonte. That doesn't include the two great Moorish palaces (the Alcazar in Seville and Alhambra in Granada).

I loved the passage tombs in Antequerra (between Granada and Ronda). There is a great museum and rarely visited tombs - all free. When we went the only visitors were local school groups.

Brad, Murcia province, at least the part between Murcia city and Almeria, isn’t on most people’s radar as a tourist destination and has no resemblance to the Costa Del Sol. Along the coast there are towns popular with tourists but they mainly Spaniards, with the exception of the Benidorm area.

"For me Murcia is too close to the dreaded (by me) Costa del Sol"

Are you confusing Murcia with Malaga? Murcia is over 200 miles from Costa del Sol and the city of Murcia is inland anyway. Murcia region's coast is called Costa Cálida - some of its developed, but much isn't, though there are golf courses for sure.

PS Benidorm is in the Valencia autonomous community, not La Región de Murcia.

To the OP - with 14/15 days, I would stick to Andalucia + Gibraltar, rather than spreading yourself too thinly. There is a lot to cover in just those areas alone (more than you could possibly do in a fortnight anyway). Save the East coast for a future visit, perhaps. There isn't much to see in Murcia city - about a day's worth - although more in the rest of the region, of course