Go for the trailer option in my view - but not necessarily the Erde. I looked at this years ago when I got fed up trying to cram everything into the car and a roof box - only to find the wife had put another three bags in the hall when I thought I'd just got everything in - and we were only going off for the weekend! We ended up picking up a second hand Brenderup with a hard top and roof bars. We put 4 Thule bike carriers on this and then kept all the camping gear in it, and it's been brilliant. The Brenderup has suspension, unlike the Erde, and towing it is a breeze. It's also small enough to unhitch and manhandle, even fully loaded and with the bikes on top, so manoeuvring in tight spaces isn't an issue. It's been a boon for shifting other stuff around - furniture for instance - and also trips to the tip. I've got a separate Atera Strada tow ball mounted bike rack for when we want to take bikes but not the camping gear. Now I'm about to get my T6 camper at last, I'm weighing up whether to keep the trailer.