I’ve got a 90 Hard Top, and it’s possible to get one bike in by removing the front wheel and lying it on it’s side across the wheel boxes. It’s not a very long load bay. Any slightly unusual bike can be difficult to load (ie anything with mudguards or racks). You can carry stuff under the bike, and even pile stuff on top, but it gets a bit disorganised, especially if the bike is dirty!
If you have an open tub it might be possible to put some runners down to stand the bikes upright and clamp the forks etc.
I’m not sure how comfy the seats are in a CSW, especially for adults – it’s been a while since I looked at one, but I don’t think I’d like to be a passenger on a long journey.