I know I'm speaking heresy here but....  In the last year I 'tamed' 2 young
guys about this age and a 1/12 year old guy all of whom had lived outside
and woud not let anyone touch them.  One  I kept & the other two were
successfully adopted.  I never used a crate but I do have a 2nd bathroom
that I could put them in for a few days & an attached (also closed off
room).  I made the bathroom their 'safe' place & put the litter box in there
& the food dishes right at the door as I don't think they normally like to
eat too close to box.  I admit that i had to crawl under the bed a few times
but all ended up sleeping on my bed in a couple of weeks.  I have one cat
( the kitten I kept) who is particularly sweet and he was invaluable in
drawing out the second kitty.  The new guy followed him around like a puppy
dog & ultimately just made himself at home.  Maybe I was lucky but it did
work out really well.  I did take them all to the vet pretty quickly as I
was concerned about fleas & any medical problems that might impact on my
cats.  None of them liked it but then neither do mine!