we went out with our child shortly after she was born around 4 months, no real problems.  Here are some things i learned
I would suggest patience
if it is just you and the wife an the baby it is easier to coordinate nap schedules, with others there more people have to coordinate, especially other children. 
go somehwere you can run the fan or AC it is goodf white noise for the child as they nap
Plan out your driving time (time you leave) so the child will sleep in the car.  as to not mess up their napping routine
A pack and play crib will be your best friend and fits nicely on a dinette that is made into a bed but without the coushions
Think about diaper disposal, as to not stink up your rig,
Be prepared to pack many more items. 
Get them started young, take lots of picturs, and enjoy your travels with them.