The real question here isn’t so much about potato appearance, but more so how the potatoes will transport and be served in regard to acceptable, safe temperature. Food safety is key here and when prepared food drops into a tepid (neither refrigerated or hot) range, this may compromise food safety. I suggest cooling the prepared potatoes and keeping them refrigerated until transported and ready to reheat – Or, transport using high tech food warmer cabinets (see below link). Either way, consider taking along (or renting at the event) a portable stove or oven to reheat the potatoes to proper temperature to avoid potential health or food safety concerns.

https://idahopotato.com/dr-potato/how-to-hold-potatoes-at-serving-temperature-for-an-extended-period-of-time.