We sailed with most of the major lines with husband's wheelchair until travel insurance became impossible 4 years ago. Generally the larger and newer the ship the more accessible it is and it is better to check out the ship than the cruise line. So a line like, say, NCL, has some fantastically accessible ships with disabled friendly cabins and also has some older ships that are not so good mobility-wise. If you need an accessible cabin (and some of the modern ones are fantastic) then you will need to book AGES in advance. We could not do that as we had to grab last minute chances while husband was well so we almost never got a wheelchair cabin. But if you take a manual wheelchair and your wife can manage to walk into the cabin and into the bathroom (there maybe quite a large step) then you can do that and it worked fine for us for years (but he could not do it now). If you take any electric mobility equipment some lines will not allow it on board unless you are in a wheelchair cabin. P&O are notorious for this unless their crazy policy has changed in the last 4 years, you could not even take one of the little folding scooters that fit easily in the wardrobe and take up less space than a folded manual chair. To be honest P&O were our least favourite for other reasons too. I would recommend the American lines as best for service and accessibility - Princess, Holland America, Celebrity, NCL's newer ships,. If you fancy a splurge then Oceania (the cruise line not the P&O ship) are the best ever - but not the Riviera without checking carefully as the entrance gangway was not accessible at all even though they had wheelchair cabins the only way to get them on board was to be carried up a 45 degree stepped gangway (probably put right my now as there were numerous complaints including ours). We never cruised Saga, Jenny's suggestion is certainly worth checking out but I think their ships are quite small, there might be issues if the sea is rough (but I am a bad sailor too - my husband would only take me on 100,000+ tonnes ships otherwise I got too seasick !!).
