I have a 27′ long Trailer that sleeps 8 and when we travel to the east coast we sleep in it along the way. is it required to have a Mezuzah on it?
I understand that the trailer is not intended for permanent dwelling, but only for temporary living, such as on trips and the like. Under this assumption, there is no obligation of mezuzah, because the dwelling is inherently transient. If the caravan would be used for permanent dwelling, some say that the the a mezuzah must be fixed, but without a berachah.
Souces: Shulchan Aruch (YD 186:11) rules that a temporary dwelling (such as a sukkah) is exempt from mezuzah; see Shaarei Ezra (77); Chovas Hadar (chap. 4, no. 6); Yalkut Yosef, Sova Semachos p. 573.