Small animals in the Southwest

For the first time with our RV we are going out west this fall. We intend to go to Nevada, Arizona, New Mexico, and Texas. Should I be worried about scorpions or snakes getting into the RV and if so how do I prevent it. We are staying in RV parks not out in the desert so I don't know how much of a problem this would be.
We have a 36 ft. Pace Arrow.

Also I have heard of some form of illness that dogs can catch out West and am concerned for my Yorkie as he is also diabetic. Any information on this would also be helpful, as to what it is and any special medicines I should take or watch out for.

Thank you.