TT's advise is solid. That's pretty much how I do it too but it also depends on how many days I'm fishing.
I've got a 2 hour drive for steelhead and I'll often stay over a few days. I'm usually the first one there and have my fishing pack all loaded up before I get there. I've got my base layers on under street clothes so throw on other layers, waders/boots, lace up the rod and I'm on my way. When I have a day trip, I'll sometimes pull into a rest stop and get my waders on before I get there and change afterwards.
Once I'm to my destination for a few days of fishing, it's easy. I get ready at the model, drive to my location then lace the rod up and I'm ready to hike. I also leave my boots on between spots. They come off only at the end of the day. This is one of the reasons I value a comfortable pair of waders. Breathability and fit are essential for me.
The trout/smallmouth streams I fish are local enough and there is plenty of isolation for me to change in/out of wading gear. I pull the cover over the cargo area of my Jeep before I head out. Always. Rod tubes bags, everything goes back there.
~*~Leave only your footprints~*~