Holy Cow, Luckygirl! Road warrior, you are!
I don't think I've ever done more than 11 or 12 shops (spread over 2,000 miles, 3 days on the road).
breestjon brings up a great point. When you read veteran shoppers completing 6, 10 or even 15 shops in a day, keep in mind all shops are not created equal. None of us are out trying to complete 10 new to us shops which all require a minimum of 30 minutes or more on site with heavy narrative reports due by midnight the same day. Make sure your day has more familiar to you with only one or two new ones and a good mix of quick and easy with some longer shops. Balancing short and long reports with various deadlines is also important. Very few people can submit good work when they leave home at 8 am only to return 10 hours later and work on reports until 2 or 3 in the morning. Find out which MSCs have non-negotiable same day submission requirements and which are more flexible. Keep in mind some allowing 24 or even 48 hours will still require reports submitted by the midnight if it is the last allowable shopping day. Because routing is vital to making money, if a longer day on the road will be more cost effective, don't hesitate to ask for an extension to the following day for reports. Many schedulers are or have been shoppers. They know how it works.
3. I map the order I am going to do my shops ahead of time. I take into account store hours, traffic, etc.
Anytime a new shop is created in the database, it is automatically added to my calendar. A new task is then automatically created in my to-do app (Todoist) with the due date set to the shop date. There's a note attached to the task which has two links, one that will open my GPS app (Waze) pre-loaded with the location's address, and another to the MSC's website. (The note also includes any notes I included in the original form when adding the shop.) When I mark the shop task as completed, a second task is automatically created for the report, with the due date of that task set to the report due date I specified in the original form (usually the same or next day). When I complete the report task, it marks the shop as 'finished' back in the database, and adds the value of the shop to the "pending payment" amount for the respective MSC.