Depending on the time of year, you might be able to book a double occupancy room with somebody with whom you aren’t overly familiar and then once at the hotel see how much extra they’d charge for a 2nd room. On one occasion, during the high season, I was told $75 or $100, I forget which, so $350 for each of us (cheaper than booking single occupancy in advance) which we didn’t take. On another, in lower season, I was charged $25 extra which my friend and I DID take. In my case, I was prepared to room with both of the people and hoped for the best. In the situation of this thread when you’re dealing with strangers, you wouldn’t want to count on the hotel being able to offer you a good deal on the extra room, but it’s a very real possibility that it could work for you.