Let me answer your question, in part, by first offering some of the things which cause shoppers to run away, in no particular order:
1. Sub-par fees. Shopping is a business, not a charity.
2. Requirements to shop places where one would not want to be caught dead.
3. Describing a shop as "fun." This is a profession, not a game.
4. Schedulers who do not respond to communications.
5. Editors who don't know English, who haven't read the guidelines, and who invent requirements or lambast one for proper English
6. MSCs which do not pay on time.
7. Repeated, redundant, e-mail blasts.
8. Schedulers who beg the "urgency" of a ship only to not assign it.
9. Pitiful bonuses. If it is important, put money on the line. Bonuses of $1 are insulting.
10. Schedulers who have no idea of geography. If a shop is 100s of miles away, don't even ask unless you offer a fantastic fee.
IMO, the best boards to be on are Jobslinger and MSJobboard. The former is tightly connected to Sassie. The latter is exclusive to Shopmetrics. Faith Perceptions is on Prophet which puts you at a disadvantage as there is no consolidated job board connected with Prophet. However, you could backdoor onto Jobslinger by posting on Volition. One can also post openings on this board, but not this forum,
Titles should be straight forward. Type of shop, location, pay. Fancy titles don't attract; they patronize.
Fees should be reasonable. Consider the amount of time to travel, round trip to the shop, the amount of time one must spend at the shop, the time it takes to produce a report. And then consider the quality of report desired and the fact that the shopper invests her/his time and travel not knowing if the MSC will pay on time, pay at all, or nit-pick with multiple editing requests. If the MSC cannot offer a fee that allows the shopper to perform the shop at a profit, not many shoppers & especially not many good shoppers will take the assignment.
Given that the locations you need to fill are away from major population centers and the type of shop is one that not every shopper would feel comfortable completing, it is good that you are hard working. Good luck!