Hitchhiking with a baby
Babies are very open to the experience, in the sense that they don't even notice anything. They sleep through it or just play with you the way they'd do at home. They get hungry just as often, which is fine if you're exclusively breastfeeding. If he needs extra yummies, think you might have to feed him on the back seat of someone else's car. Plan your food accordingly. Bananas work wonders.
If you're on reuseable diapers, you'll need to wash them as they get used and dry them on your backpack or something like that. That cuts down significantly on how many you bring with you. Access to water for cleaning is normally not problematic. If all your absorbant fabric is wet, you can use a handful of toilet paper instead.
If you're on throwaway diapers, then you'll need a freaking huge backpack for when you run out and need to get a new box. If you get the small boxes, you're likely to run out before finding a shop that sells more.
When it's time to sleep, the baby will just do that. It's useful to have something to strap her to your body, so you can get out of the car or walk around without waking her up. You can keep hitching through the night, but that will make for a cranky baby in the morning. If you can set up camp somewhere, she'll be thankful.
Breastfed babies are incredibly tough. You don't have to worry about her catching a bug. Even if you're in India and she's touching everything and sucking her hands. You'll be sick way more often than her. And she'll heal faster too.
Security and regulations
Drivers love babies. Moreover, most of them don't care if you aren't carrying a car-accessory approved by the authorities. If you have your baby strapped to your body and wear the seatbelt under it, as in "between the baby and you", it provides pretty good security in case of crash. If you wear the seat-belt over the baby and there is a crash, you'll just squish it with your own weight so please don't do that.
In addition to that, many drivers drive around with an empty baby seat. Those will feel compeled to pick you up.