Compare IM Texas and IM Louisville

I did Texas this year, and want to do another IM next year.  I was considering Florida, but I know my strength is in heat.  I hate being cold and a chilly bike followed by a run mostly in the dark, and possibly cold just doesn't sound like the best choice for me.  So my main issue is how does the hillier bike compare with the rollers?  I live in Southern Arizona and usually get 1500 - 2K of climbing on my rides of 50 - 60 miles.  I can find bigger climbs if needed.