I had some similar worries a few months back, with a similar background. I had just switched my snake to f/t, she ate the rat right away the first time, and was then hesitant for a few weeks. She'll eat consistently now provided I feed her late at night and don't disturb her for an hour or so... she also seems to like her rats towel dried, silly snake. Just keep trying and see what happens. No need to worry anytime soon.
As far as hanging out on the cooler side, what are the temps on the cool side?? I ended up getting a space heater to increase the ambient temps from 71 to 76 so I dont have to worry anymore. Bloods LIKE to be cooler than other snakes, so they'll often hang out where its cool. Its up to you to maintain their environment so they can hang out wherever they want and still maintain an acceptable body temperature. People will tell you they'll go warm up when they need to, but when fall started, my blood maintained a body temp of 70 degrees for a week, and I'm not exactly sure if thats healthy or not.
My best advice is for you to get a temp gun. You can point it right at your snake and find out what they're body temperature is. That way you know if they're cold or hot, and adjust your caging accordingly. TEMP GUNS ROCK!!! I can't believe it took me 2 years to get one, they're dirt cheap IMO.