Well done on choosing to rehome an older cat, I admire your decision. I'm not sure I could choose an older cat myself having recently gone through the pain and heartache of losing my nearly 16 year old cat. In the past 2 years my friends have lost their cats at ages 13, 14 and 16.
Insurance costs also rocket from the age of 10 onwards and there are large excesses to pay.
Having said that, an older cat is good as a first cat, a lot calmer and less destructive. It took me a good 6 months to properly bond with Tabitha when she was a kitten, she was so hyperactive, climbing curtains and scratching furniture and I was so houseproud (still am), However, after that our bond was unbreakable and I tolerated her mischievous ways in a way that friends found surprising (eg bringing in live birds and rodents). I recently looked after a year old cat for a couple of weeks and I found the experience fairly exhausting and my furniture, carpets and rugs bear her scratch marks. I don't think I would choose another kitten when the time comes for me to take on another cat.
My second cat came to me when he was 18 months, past the kitten stage but still young. I think it's harder to form a really close bond with an adult cat but Bernard and I get along very well and we've become closer since Tabitha died. He's always been so well behaved (well, apart from play chasing Tabitha when she was ill), he's not very bright but he loves other cats.
I agree with those who say your cat will find his own sleeping spot. The only time my cats ever used their expensive beds was when they were at the cattery - they like the familiar smell of home. Your cat may not like the cardboard box, cats never do what you ask them to do. And give him time and space to adjust to his new surroundings, it'll take him at least a couple of days to feel comfortable with you