You have an almost zero chance of a snake either going in your house, or of being bitten by one... Snakes will only bite as an ABSOLUTE last resort. The snake bites you see on TV people getting fall into one of the following categories:
Stepping on an unsuspecting snake
Feeding them mice (pet snakes, or zoo keepers and the like)
People who harvest venom
People doing
something stupid.
Subset of "something stupid": Picking them up by the tail to play with them, caging wild snakes not intended to be pets, harassing snakes in the wild, etc.
The chance of you opening your door, and a snake just deciding it wants to wander in, are pretty much nil. Snakes LOVE to be left alone.
If you had a snake under your house, you would be lucky, if nothing else because they will eat any rodents and bugs that they can find under there. The inside of a humans house is the last place in the world they would want to be.
The same thing is true of spiders and most wild animals that are not rabid: They want to be left alone. They will not attack you. You have nothing to fear
Now, if you want to be
concerned about something as opposed to afraid, you should be very vigilant about ticks. Lyme's disease is a very un-fun disease (trust me, I have had it before). Make sure if you have any pets you put flea AND tick killer on them 12 months a year, regardless of the weather outside.