I moved up from a travel trailer towed by a Ford Explorer to a class A this year. First to a Thor ACE 27.1, which turned out to be a poor handling, poor quality dog. After three months I traded it in on a Winnebago Vista 27N. I absolutely love the 27N; drives well, good quality, great storage, haven't found anything I don't like about it. For me and the cat it's a good size, but I think it could be too tight for a couple full-timing.
Back to your question about getting used to driving a "huge" class A. I am a 68 year ol'e lady and never drove anything this big before. It took me about 200 miles to get confident about staying centered in my lane - check both mirrors continously. As far as cornering, even with my CR-V in tow, it is easier than towing a travel trailer. Just have to be aware that the tail swings wide. It could hit something if you turn out too quickly from the curb or gas pump. Now that I have driven it about 3500 miles, I love it. I like the visibility from the big panoramic windows and like sitting high.