Are you asking about 37 ft vs 38-40? Obviously not much difference between 37 and 38, but you may notice 37 vs 40. Less living space inside, but easier to fit on those shorter campsites. Not that finding a site for a 40 footer is any big deal, but if you are accustomed to going places with a 30 footer, then either the 37 or the 40 is going to push you towards different sites.
Are you aware that the Caymans and similar models in those years used the Roadmaster R4R& RR4R chassis that had a serious problem with the trailing arm rear suspension? If it hasn't already been fixed, beware of the cost of repair. Read this article to seee if it applies:
https://sourcerv.com/RoadmasterR4R_FMC1109.pdf