I know this thread is about Car Hire Rita,but I just wanted to also let people know about driving from the Tortosa area to Castellon airport.I have dropped off & picked up recently here & the Journey time from my neck of the woods (Els Reguers) took around 1 Hour 15 Mins using the AP7 motorway.Toll cost Euros 8.90 each way from L'Aldea.What can be a nightmare is  leaving the motorway & getting on the C13 (Road on which the airport is off of).Its an absolute nightmare!!!!! The road climbs uphill for most of the way & is single lane (except for about a 2 KM stretch,where it is 2 lanes) and seems to be loaded with heavy lorries!!!! Hence a very,very slow approach to the airport.
Now the pick up & drop off was for the Ryanair Bristol flight,which may just coincide with heavy traffic on the C13,this I am not sure of? Anyway this will add extra time to the Journey.The N340 is also an option & takes about 1 Hour 30 Mins for me in rush hour traffic.Good bypass now around Vineros,Benicarlo & Peniscola,but of course this is single lane all the way.The CV10 is another option,but look at around 1 hour 40 mins from the Tortosa area.
Still longer in journey time (although around the same distance I think) than driving to Reus! (using N340 & A7 or AP7) But of course the reduction in fights into Reus means Castellon is the nearest airport if you want to fly into Bristol.
I feel the best option in future for me on the outward journey is Hife bus to El Prat (from Tortosa) only 2 hours 15 mins (or sometimes less) around Euros 21 (Cheaper if buying multi tickets) & then Easyjet into Bristol.(better depart times).The inward times for Easyjet are not so great,especially if you want to use Public transport in both Countries.So maybe into Castelleon may be worth it,providing a way round the C13 can be found? (Using last part of journey on the CV10 maybe? then joining the C13 from its opposite end?) Anyway,just some thoughts,which I hope can be of assistance to would be TF folks thinking about using Castellon airport.