hi there! my fianncee and i are avid campers too and take our yorkie Millie with us everytime and shes an absolute star, she loves it!! weve taken her with us since she was about 10 weeks old! when ever she comes in the car, we put her harness on her and put her on her doggie seat belt which is the best buy i think ive ever bought! its an amazing piece of kit that works a treat. ive had to do many emergency stops with Millie in the back seat on her seat belt and shes been completely fine. i would suggest only using it on the back seat though as if your yorkie is like mine, if she get the chance to sit on your lap she will and because of the position of the front seatbelt clip, she can reach your lap. heres the link to the seat belt on ebay that we bought:
SAFETY SEAT BELT RESTRAINT HARNESS FOR DOG/DOGS *NEW* | eBay UK theyre so good we bought 2 of them! one for each of our cars!!
when camping, the only tips i would give is buy a retractable lead for your yorkie as they tend to escape underneath the tent flaps when they want too, but with a retractable lead you can keep them on it when needed and choose the length you want. Also make sure you take your yorkies blanket as the tempreture can drop an awfull lot at night for them.
Happy camping!!