RSVP Dilemmas, Venues and Caravans

We’re getting married in a beautiful secluded lodge style hotel in Wales just an hour from where we live. As part of the deal with the hotel we get a discount on all guest accommodation but all 18 rooms HAVE to be paid for whether they’re occupied or not. My problem is both our families are based in Yorkshire along with a lot of the other guests. People will be coming a very long way so will need to stay somewhere, there aren’t any alternatives nearby and even with the discount rooms are around £100. My fear is the cost of staying over will put people off from coming at all so I’ll be missing guests and have to add the cost of the empty rooms to my bill. I’ve already had people asking if I know anywhere nearby for their caravan! I don’t want to pressure people into coming but I don’t want to lose guests either. I’m stuck.