The Costa Blanca and the Costa Dorada are in the same country and the same continent. So there can't be any problems (unless, perhaps, you were thinking of going the long way round via, say, India or China?)
;-)
You don't mean continent do you. Costa Blanca and Cost Dorada are the just two coastal areas of Spain. You should be able to drive anywhere in Spain if you have unlimited mileage.
As above ....... plus I thought Costa Dorara was above Costa Blanca, so you'd drive down to Costa Blanca (or up to Costa Dorada) .... maybe I should google this first ........ oh well, too late :P
It won't be a problem, as long as the car hire company has offices in both the pick up and drop off locations. Most car hire companies will ask where you are picking up and dropping off the car. I presume you are staying in Spain.
erm i might go via india lol @buenchico thanks for replys i wanna drive from orihuela coasta costa blanca to salou costa dorada then back week later i know it takes around 6 hrs one way