Hi SoJim,
Time management is a chore, isn't it?
With that many shops under your belt you should have an idea of some things that speed us along. But here goes.
Route planning you seem to have down,
Becoming an expert in the shops will speed preparation and imputing time,
Multiples of the same shop in the same day helps,
Doing shops for MSPs you have experience with will help avoid unfamiliar websites,
Look into mobile tools (tablets, laptops, etc) with possible WiFi access to enter shops on the road,
Avoiding procrastination helps too. But then I wouldn't be answering your question.
Good luck!
Happily shopping Rhode Island and nearby Massachusetts and Connecticut