Given the time zone he's in, it might take a few hours for @Britsimon to response, but I can say that you don't have to find a 'host' or someone to stay with.
You will, however, need to have an address to send the GC to. You can change this address at any time up to the point of entry. It can't be a PO Box and has to be a street address, but you can have it sent to a hotel etc.
Thanks. I was asking this because the officer at the POE might ask to see proof of funds. Oh God, I haven't even won yet and I'm worrying about all this stuff.
Thanks anyway. I'll wait for britsimon's respond too.