Bunnies - how do you keep yours?

My bunny is litter trained and completely free. I do not believe in caging rabbits as they are such big and active animals and need plenty of space. He comes and goes when he pleases. I cannot get him a friend as he was never socialised as a baby and cannot tolerate company. I rescued him from someone I spoke to on the internet who clearly could not be bothered with him. He was in such an awful state of neglect. He had a parasite,eye infection,was skinny and had total tooth decay. He had been fed cereal like rice crispies and half starved. I have to take him to the vets at least once a month as he is not very healthy. I love him to bits and want to make up for his awful start. I am sorry if that was too much information!