snakes can and WILL burrow to the bottom of the substrate; you should always measure every part your snake can reach, especially the hottest part. PLEASE unplug the UTH IMMEDIATELY! ALL sources of heat MUST be regulated! non-negotiable. this is why she won't settle in, she can't regulate properly and is uncomfortable!
again, you should be measuring the bottom of the tank for the hot spot. also the temperature should not drop below 75° anywhere, ambient or otherwise. the infrared temp gun is an awesome tool, though i don't use the exo-terra one. i would also recommend one of these digital thermometer/hygrometers for measuring ambient temps, this is an amazon link but i found mine at walmart.
bulbs help raise ambient temps but i don't use them so i can't help here. and i'm sure the bottom of the enclosure over the hot side is well above 100°. you need to measure the absolute bottom. and yes i do believe the hides look to be too small.
also PLEASE read through the stickied post MrSully provided to ensure your set-up is providing everything your snake needs.