no, you will be fine as long as you are prepared...lots of warm clothes and layers...the thing to do is keep warm during the day. We went away at easter in the crusader for a couple of years and the first time it was about 2 degrees...we hadn't gone prepared as the week before was blazing hot sun...we got really cold during the day and it was really hard to warm up in the evening in the camper. Have you got a heater? And if you can, get an electric blanket or mattress topper as we found them invaluable as you could leave it on all night long, so we were always toasty in bed.
We are also thinking about going away in October but haven't booked anywhere yet! Think we will be waiting to see how the weather is looking nearer the time!
Pete