SpadesFlush,
Short answer - It's 1) the way I plan, 2) many times there are updates to several of the database [pushpin files] and 3) I generally have several trips [and variations thereto] going at one time - I'm retired -
Long answer - It's better for me the way I plan trips - Once we decide where we want to go - first step - I make a tentative routing to the main sightseeing places and do a sanity check and opitimize the stops. Then I will add in [my new] campground GPX which includes state parks, passport america campgrounds, COE campgrounds, etc. to get my overnight stays and total number of days in order to make reservations. [Insert my wish for a calendar with start date here again, rather than Day 1, Day 2, etc.].That generally causes some re-routing - and optimizing which to me is better done with all the dead weight [pushpins, etc.] removed, then i remove the campground GPX pushpins [I use the MS campground icons to mark my route once I locate them, but you can't see them unless you zoom in real low], save the file for family and freinds as an itinerary, and this file and its stop numbers matches my 3 ring notebook by stop number for reservations. [Again, I would ask that Home / Start be made 0 [zero] so that the first stop [Stop 1] is actually the first stop !
I will then add the brand store GPX to a new saved file just for a driving file, as this will many more stops - rest stops, lunch stops, etc. and as I travel I eliminate the covered territory and S&T then tells me the mileage for the remainder of the trip. I can also do the "Copy Map" [after zooming in on the appropriate part of the map for the current day travel] and "Copy Directions" and paste into MS Word each day in order to give us [and our traveling partners] a birdeye view and detail turns of the route [I just delete the excess directions except for Day 1 before printing]. I also will do like you suggested with the brand store file for sightseeing and shopping itineraries while we are staying in an area.
HTH,
Tom