The best way to find a hotel shop in the city you want on the day you need it is to already have a very good track record with that MSC and perhaps even with that scheduler. Then, email your dates and locations and ask if there is any chance that they can hold a hotel shop for you that matches your needs. If you are an IMSC member, also email the president and ask for access to the secret FB page for schedulers and shoppers that they have. Many schedulers hang out and post shops there because they have been to IMSC conferences and count on IMSC members to be experienced and well trained.
I also strongly suggest that you look for Airbnb accommodations that have high speed Internet. They can save you a bundle and allow you to write those reports more easily.
When I do a route, say, from DC to New York City and then go on to visit family further north, it matters not that I may do no shops between DC and NYC, for tax purposes. However, it matters greatly that the legs of my trip from NYC to CT and back as far as NYC are not counted a business expenses. So, bridge toll into NYC for 3 days of shopping there: deductible. Once I leave NYC none of the tolls between there and CT or on return as far as the closest exit for NCY: not deductible. From there to home: deductible.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.