I am 70 this month and have been going through this process. Basically, there is little out there for either the young or the older members of society and yet, in many ways, we are both after similar accommodation.
Like the OP I have been caring for my mother - for about 10 or 12 years in my case. She was in a bungalow which she moved into when she was and my father were in their late 60s so staying there was quite possible for quite a long period of that time. She had the bathroom made into a wet room which helped.
The difficulties were the up-keep - she had quite a large garden and my father was the gardener. On her own she could not do what two people did. Luckily she made a PoA or she would have been destitute pretty quickly. This seemed to come from a combination of Dad always looking after the finances, grief and the very early stages of Alzheimer's. A decade ago it was my insight into what "isolation" actually means. Just providing people with visitors or, as we did for about three years before Mum went into care last October, providing visiting carers does not stop the effects of isolation. This has taken its toll on my health as well as Mum's so I certainly don't want my own daughter to be put in the same position. I feel as if I am just starting my retirement but, on the other hand, it has given me an insight into what to look for. The questions are - does it exist and how soon do you plan to meet possible changes.
I have looked at various retirement flats. While I may be able to afford the flat the ground rent and the service charges have often been a third of my income. For that some are pristine and obviously cared for and some certainly are not. I thought they would offer a sense of community but again, some do but some are like a visit to the morgue. There are reselling issues too. The government has talked about changing the laws covering leasehold - England is anomalous in actually having them - but the builders of these flats see the on going income as part of their business plan so are fighting to keep them. I know of one single person and one couple who are moving because they can no longer afford the charges. They only go up! This doesn't mean these aren't the solution for some but do check everything out carefully.
Bungalows were the next thing I checked out. My worry with these is the possible isolation and the fact that most have quite large gardens. I could manage with a smallish bungalow on a small plot but they are few and far between. Because few new bungalows are being built they fetch quite a premium too. You also need to think about what you would need to pay for when you are a) on you own or b) no longer able.
Currently I am looking at ordinary flats. I would like to be in a village as I enjoy that level of community but, again such things are rare. Whatever I find will be a compromise but one thing is sure, forums like this can give a wealth of information from those who have been there and done that 
