Yeah after winter when the pond gets over 18 to 20C they can go out, will handle winter where you are. They just need to have summer to get use to the elements. Then as winter dawns they slowly wind down, once temp gets under 18C stop feeding.
I think your tanks is probably more than sufficient, moving the turt around probably isnt doing much for her independence :lol:
Can put her outside on really hot days but watch out for cold drafts/wind, especially at this time of year. And must have access to shade, and preferably water. Wrong time of year to be doing so really, but then again there is still a heap of heat in that sun when it shows it face. I was reflecting the sun off my whiteness today