Certainly NOT a dumb question.
All those items are indeed what i take along Plus a small digital camera or i use the one on my mobile I might even do a small movie with commentry as well helps me out later.
No wall or floor for that matter will be perfect (OH!!!! for the day it comes along) small variations are normal but if you put the level on the wall and it's way out or you can stick your finger in between the level and the wall then the client will need to be made aware that some sort of wall prep will have to be allowed for. Be Honest and polite and communicate your concerns, people value this and will take it into consideration when selecting the right tradesperson for the job.
