I traveled to Namibia with my LO (a three day drive!) when she was aged 9 months - it was not half as bad as I thought it would be. They do sleep alot and having loads of toys at hand to swop and change with is a must.
You do have to make many stops and do make space for you to sit next to your LO - it helps alot when the journey gets very very long!
Also, you can get those DVD players you strap to the back of your car seat. Get something age related like Tiny love or telly tubbies. I am not a fan of too much TV, but it helps to destract you LO when nothing else works...
Latly, keep loads of snack foods for baby - if he is holding and chewing on snacks, it also keeps them busy - however, sit next to him at this time and make sure his seat is in the upright position. This will stop food from sliding down and causing him to choke. Even beter - use one of those little bag-things you can place fruit in and have him suck on that. Keep him busy and your mind at ease, plus it is super healthy - bonus
We also had some fun baby song CD's in the car, I jumped and clapped and sang along to everything! Not just my LO thought this was funny - DH had a good old laugh aswell
In regards to the passport, you will need one. When you apply for this, remember you need mom and dad's signature. So remember to take your ID and passports with when applying for his.