Hi Tony
I've mainly come on to offer some encouragement.
We have a Landranger 5900L (97) We have had this for 4 years now and towed extensively in the UK, Ireland Brittany and in summer 2003 for 2.5+K miles through Holland, France, Germany, Austria, Switzerland and Belguim. This is our second van and considerably larger than our previous one. We do, however, enjoy the extra living space and have managed to get into all the sites we've wanted to. When things get tight one of us drives while the other(s) hop-out and watch the blind spots.
We tow with a Vauxhall Monterey (re-badged Isuzu Trooper) 4x4 and with this combination we've managed all the hills, etc. We have encountered some pretty narrow roads particularly single track ones on the Kintyre Peninsula in Scotland and Lleyn Peninsula in Wales almost without mishap. The only scrape, literally, was when I caught front offside of the van on a high kerb in a Brittany petrol station - a lond day's driving and a misunderstanding of my son's directions are my excuses??!
Sutton Bank is the only place where I have actually encountered a ban on caravans. I usually check the large scale road map carefully and, also, ask the destination caravan site for advice if I'm unsure. If there's a caravan site at the end of the road it's do-able with care. I find other road users are courteous and considerate when we meet in tight spots.
There are some warning about unsuitable roads in the Caravan Club Handbook if you're a member. Both Caravan and Camping and Caravan Clubs give recommended routes to their sites in their respective books.
A word of caution on another level - we've had aquite few problems with damp on our 'van so I'd advise regular damp checks. I've, also, gained quite a bit of knowledge of carrying out minor repairs on the Landranger and I'd be glad to advise if you need any help on that front.
Happy Landranging
Regards Tim