The first cattery I used my cat hated, changed to another and he loves it. Comes back with a glossy coat, really fussy and meows the whole way home as though he's telling me all about his hols! He can be quite a nervous cat but he's definitely fine.
I once left him at home and a friend went round to feed him etc... Never again. Whilst the friend was fantastic - went twice a day, used to sit in the garden sunbathing for an hour with a book to give him some company! - he obviously felt lonely and got bored towards the end. I came back to find he'd been in a fight a day or two before I got home, which resulted in a massive abscess above his eye and a trip to the vets.
Any decent cattery will be happy to let you look around and see their facilities. The first one I used had indoor and outdoor sections to each pen, but the current one is indoor only.
Putting them in the cattery for a weekend is a really good idea. It will be long enough for them to settle in, but short enough for them not to feel abandoned. The cattery I use has pens that house 1, 2 or 3 cats, so if you find a similar one they will be able to stay together.
You will definitely need vaccinations as any reputable cattery won't accept cats without them. If you let us know the rough area you live in, we may be able to give you some recommendations.