You should be just fine.
Just remember our ancestors: they would have NEVER known this early that they were preggo and they rode horses and had rough carriage rides and lifted heavy buckets of water, etc. and their babies were just fine.
Babies are, in general, tough! So I wouldn't worry about baby too much. But, then again, good mamas ALWAYS worry about their babies, don't they?
As far as you go, I would just be sure to make sure to stop and walk around every several hours and make sure that you are moving your legs around/wiggling your toes while in the car to keep that blood flowing well in the legs (which is good advice for ANYONE on a long car trip). Drink lots of water too.
If nothing else, this trip gives you and your DH a lot of one-on-one time to discuss baby names--right?!
Good luck--have a safe trip!