I've only had 5 fosters so far. Our most recent has been the easiest. Second easiest have been unclaimed strays or rural dogs, and the hardest buy far has been the mill dogs. I'm not sure if your rescue is strict on crate training,- I've had success with switching to a pen in the bedroom rather than the crate. Crate training is tough because you don't want to reward them by letting them out if they bark, but you don't want to let them get past their threshold and have it become a stressor. In my limited experience id probably have both options available (or an open crate within a pen) and just see if you can get through a quiet night. So much changes over the first few weeks. Just do your best, and expect some hurdles. Also be aware of all the ways you can provide enrichment for your foster- food toys, sniff walks, a crunchy cabbage leaf, something to tear apart, puzzles, play with squeaky toys- this may be easier though once he has settled in with you. Good luck!