In reply to dread-i:
Not the first date, but within a month of meeting so possibly our 5th/6th date my now wife went camping with me and some friends in Buttermere. It was very cold so I gave her my sleeping bag and I used hers...it was not up to the task!
Anyway, she took to the whole thing extremely well, never complained, was happy the entire time, including a nice big walk over the tops followed by copious amounts of beer. I knew she was the one then.
Not weird for us on this site, but everyone else I knew who wasn't outdoorsy thought it was a very weird thing to do in the first month of dating!