Hi, there are some things you should change about the corn snakes care
First of all, I would not use a heat pad because it is unnatural in the wild and in captivity snakes burrow in the substrate to escape the heat, not go toward it so i personally wouldnt use a heat mat. Instead, i would use a 24 hour heating night bulb that you never turn off, depending on your cage size/type hooked to a thermostat. For thermostats i prefer the one by catalina aquarium it is not very expensive and nearly as good as the ranco, you can get it for 40 dollars shipped from their website.
your aspen is fine, you can feed him inside the cage just make sure you put the mouse/rat on a platter or flat rock of some sort so the snake cannot ingest the substrate and get impacted.
as for the 2 hides i would only use 1 hide on the warm side, i usually put mine in the corner, because the snake might like the cold side hide just a tiny bit better even if they are exactly the same and he may just use the cold side hide just because he likes it better.
water dish should be on the cool side of the cage.
the thermostat probe should go on the warm side set at 85 degrees but not directly underneath the bulb. the cool side should be 75.
i also have a theory of my own you dont have to follow it, i just do and it works for me, i get really paranoid about my snakes. well as you probably know snakes only have 1 lung, and if they are too cramped they can get stressed out and die, that is why i use a cage the snake can completely stretch out in.
you can but i personally dont even use glass cages for snakes, i find they are hard to heat and are hard to insulate.
i use a wooden cage called a critter condo, now yes these are very expensive but they are far worth it.
they are properly insulated and retain heat for 24 hours, they have built in heating and lighting ready to go and sliding glass front doors with melamine surfaces, these are friggin awesome cages!
i change the water every 4 days or whenever it has dried up.
heres a very important piece of information i always use for hides, dont buy those caves for snakes that are so high and big they feel like a house for snake, snakes want to hide in something flat, that will protect them from the predators and elements. cork bark, in my opinion, is the perfect hide for all reptiles.
oh and if you want a great water bowl that bacteria will never develop in, ever, get the zoomed repti rock water dish, these are also awesome, look great and stay clean.
clean up feces whenever you see them, clean the cages once a month,feed every week frozen thawed.
and that should be everything you need to know for now, not trying to be a nuisance just trying to give your cornsnake the best care it can possibly have.
sorry if i treat you like an idiot lol most stuff you have right.