My first BP and my first setup... thoughts..?

[LittleTreeGuy]

So, I had plans of ordering a T8 enclosure with all the bells and whistles and having it set up for a couple of weeks to make sure I had the heat and humidity all set right where I wanted it, then I'd go snake shopping. Well... Like I said I wouldn't, I went to not one, but two reptile expos this past weekend and ended up coming home with two hides, a water dish, an older pvc style enclosure (about 2'x2'x14") and a young female mojave (she fits in my hand). I really wanted the pastel mojave, but maybe that will be snake number 2. lol. The encloser, while it is all plastic, has two 2" circles in the back for ventilation and is constructed of about 1/8 or 3/16" plastic.

So, i'm going to try to upload a photo below to show my new setup. I'm having a little bit of a hard time with temps. My house is around 65-69 F pretty much all fall/winter/spring. The enclosure came with a UTH (a very paper-thin type) that does heat up a spot pretty well. I have no problem getting that area to 90-92 using a thermostat. The problem is the cool side and ambient air temps. I think i'm going to stop after work today and pick up a second UTH for the cool side and just set that thermostat to maybe 80-83 degrees. That should help keep the bottom of the tank warm. Next is ambient temps... with the tank being kept warmer, it may rise a bit, but I'm also considering getting a CHE and cutting a hole in the top of the cage, covering with screen, and trying that. I thought if I have that on a dimmer, I can dial it back to where I want it as the seasons change. I know humidity can drop a lot with a hot hole in the top of the tank, but I don't want the snake to get cold. I live in a 100+ year old house with very large rooms, high ceilings, etc... so keeping the room heated with a space heater isn't real practical. Does this seem like a realistic approach to getting my heat up to where it should be? Right now my temps vary by a few degrees but the hot side is low to mid 80's and the cool side is low to mid 70's.

**I can't upload pics from work, but i'll try to add one later tonight.***