At what age is it acceptable to take your dog on a longer ‘trip’?

I would like to start taking her to different areas, but I live in a village and would need to take a long commute in order to even reach that. Im assuming she would sleep in the vehicles as shes a small dog whos used to her bag whenever i take her on quick errands with me, but I was wondering if the lenght of the trip would be too much for her just yet as shes only over 4 months old. I was thinking max a few hours of being in the actual area, but Im not sure if its too much for a puppy.