Sue and I packed two "dressy" outfits on our recent trip to Vegas, for shows-- HOWEVER I forgot collar stays for the long point collars on my old-fashioned dress shirt. I found that coffee stir sticks provided as part of the in-room coffee service (or wherever you find coffee service-- it will be somewhere in the hotel/motel) can be cut to length and will serve perfectly as improvised collar stays.
Use the nail clippers from your toiletries kit to cut them to length. I used the flat wooden stir sticks which happened to be available, but I am sure that the round plastic stir sticks (often preferred in off-price motel/hotels because they are cheaper) will also serve quite well.