Vistani

From Adrian's 'Guide to Barovia':The Vistani are a group of people native to the land of Barovia. They travel in tightly knit groups, usually always with horses and tents. I believe they support themselves by trade, they are the only people that I know of that are freely able to traverse The Mists to leave the realm or plane of Barovia. I guess even Strahd sees the need for commerce.
It is unfortunate that they are technically allied to Strahd but they seem rather neutral, not fully dedicated to the 'worship' of Strahd similar to those vampire spawns we met who are under his direct control. In contrast to the Barovians we met in the settled villages the nomadic Vistani are more jovial. Every night in a Vistani camp is filled with merriment, joy and drinking. Be careful of anything you buy be it objects or people, they'll try to undercut you.
These people have their own folklore and traditions. Among them is an ancient knowledge and some of their people are well practiced in the arcane arts, do not mistreat an elderly lady in a Vistani camp 'lest ye be unlucky enough to come across one that's able to curse you or affect your future. Overall, a good people to stay with on short visits. A night or two only, be safe.
Keep to your own tents, party and drink with them (to a certain degree, don't pass out or you might get robbed) and you'll be just fine. The Morninglord knows you'll need the rest, merriment and provisions before you journey on.