You can also bury those cardboard rolls most of the way...think "in-ground tornado shelter", with only the doorway showing a little.

But all these changes would have been better before putting in the snake...right now, too many changes can stress him further, as can your presence in his home turf.

A live runt-fuzzy might be helpful, especially if he still won't take f/t pinkie, but keep trying f/t...you never know? I'm sure he's hungry. Thaw pinks in cool water, I do
not recommend heating them for a rosy boa (they don't have/use heat pits the way BPs do), but do pinch-damage the nose slightly right before offering to release a
little more scent. I would try offering it from tongs with a little wiggle (away from the snake, or perpendicular to him) first, but if he's uptight about that, I'd leave it
on a plastic food-lid, either inside his hide or just outside the doorway, later evening & right before lights out. Don't keep checking him, because you might show up
just at the moment he's getting brave enough to take it. Leave it & hope. Sometimes a snake will accept food when confined with it in some type of container, but
that requires picking the snake up first, & that's generally bad for shy snakes...the stress being handled makes them forget about food. Rosy boas vary quite a bit, &
some are strong feeders (& may also be biters! ) while others are shy & overly docile (harder to get going).