A couple other things to make your life easier.
- I always get a spot grade at the first floor threshold, garage door, top of siding, and bottom windowsill of the basement windows. I always do these first so I don't forget.
- I always measure the lap on the siding, the height of one brick + one mortar joint, and one "brick" on a stamped foundation wall. That way if the client calls and says "hey, can we add a pergola/step/whatever" I can use my photos to count rows of brick and math out a good guesstimate of the height.I wouldn't trust it for adding a roof structure but it's fine for most things.
- If I need to hold my 100' or 300' tape on something, I keep masonry nails, skinny picture framing nails, woodworking clamps (with a little felt they won't damage downspouts), and bungee cords in the car. I'm a big fat guy, I don't want to get 120' from the house and have the tape fall off the corner.
GoiLawn is surprisingly useful. Any time it's more than a simple planting plan I try to pull the aerial imagery and a survey plat before heading out. That way when I get there I can see exactly what I need to locate, and what I can get off the existing documentation. I did a plan for a guy who had a front walk that was squiggly like a goat's intestinal tract. I could've spent 25 minutes pulling a grid, but instead I traced over it on the aerial photo. Done.