This is pretty much a travel question rather than real estate, so it is totally outside of my expertise and experience. I did find some information in the Tico Times Exploring Costa Rica guide that may help you:
- Your car gets a 3 month entry visa, just like any tourist, you can renew it one time.
- The fastest way is on the Interamerican highway and the trip takes 8 days minimum.
- You should get a recent book for full advice as each border crossing takes different bribes, I mean requirements.
- The trip is relatively safe since there are no wars currently in progress. Driving in the daytime is recommended however.
- you may find a more helpful guide on travel sites, try searching "drive to costa rica" on your favorite search engine.
Once your car (and you) get here, and decide to stay, you have to pay the normal duties and meet the normal requirements for residency. You can find some good information about residency in these articles:
Costa Rica retirement ways to qualify for work permitsCosta Rica customs and import duties: bringing your vehicleCosta Rica residency and attorneysKeep in mind that some of these requirements require authentication from outside the country and many lawyers recommend initiating the process from overseas before moving here.