Hi
I can only comment on the relatively small area we were in.
We were bastes in Andorra 1050 miles from Manchester .A comfortable two day drive.
I would consider tacking the ferry from Portsmouth to bilbow wane you compper the price of fuel, tolls, and accommodation I do not think there is much in it and you have a day and half rest.
From Andorra we drove into the mountains on 3 days and spent 8 hours a day off road in low box.
Be shour to plane your rout very carefully as wane you get on one of the roads you can not turn around for miles and miles they are only as wide as a landrover with very big drops 2000 ft +(scary)
In September it was 30c most day on the last day in the mountains it was fogy and we went up to the top of the ski lifts I think about 7000ft.

The highest we went was 9000ft all the motors were black smoking and the turbos were howling trying to get enough air. All the lanes were easy going all terrain tyres were good enough.
Andorra is lovely a few small towns we ware in Encamp.
One word of warning you are only aloud to take I litre of alcohol and 20 cigarettes out of Andorra,200 cigarettes are about £5.00 spirits £6.00.We were in the mountains one day and got stopped by a boarder grad at about 6000ft and he was looking for contraband
.
If they cache you with a lot they throw your car of the mountain.
This is a rang rover upside down in the trees you can not see from this pic but it is about 2000ft to the valley. There was a another one that was to far down to take a pic but it look lick it had bullet holes down the side.

Andorra La Villa is the mane town with plenty of shopping so you keep hold of the credit card do not let the wife have it there is a shop with 5 floors of perfume and a lot of designer shops.
We had a very good even at
http://www.caldea.com/ it is a spar with a roman baths ,stem rooms sorners a large indoor pool and a out door pool on the roof that you can swim to from the indoor pool and look out over the town. The restraints were very good French and Spanish .

All the local people were very friendly and helpful.
You will have a excellent time. The views are berth tacking the driving is nothing like the uk were you go for two miles and then six miles on tarmac.
I am doing the Boab Raid Asterix at Clermount Ferrand in central France in May.
I have put some moor pic on
http://community.webshots.com/album/554463994koefAHGood luck :)
David