It's a pretty plain Jane suggestion, buuut... my husband and I started a tradition of having a honeymoon every year (so we had our third honeymoon/second anniversary back in July -daww
). We decided that, for hte most part, we'll take advantage of having a car to explore this lovely country, and so, we pick some place neither of us have been to drive to. While there, we rent a little cabin or something of the like, and then just enjoy our little home away from home for the week/weekend. The first year, we went to Oakham and wandered around there and the Rutland water; very pretty! This year, we stayed at a friend's cabin up in the Penines, and had intended short drives to see Scotland and
Hadrian's Wall. Unfortunately, it was that week where the entire country was underwater, and being in the mountains, we decided it was best to stay put.
But both trips were definitely EXTREMELY enjoyable, and low key - we could go do things or not as suited us, and we got to see more of this country we love. Next year, we're going to cheat and go to Cambridge - my husband has been, but I've not, and as our baby will only be 7~ months old, we want to be less than an hour away from home in case something goes wrong and my in-laws need us to check in!