We are getting ready to make the jump from TT to a diesel pusher. Besides the 3rd axle are you gaining that much more room with a 45' vs 40'. We will have a toad, spend part of the winters in the warm...
The only draw back is that some parks cannot accommodate a 45' coach even though they can handle 40'ers. I also don't know if CA ever fixed their law but it was illegal to be over 60' long in CA. With a 45'er you will easily exceed that length with many toads.