There is a bucksaw that dissassembles into a single tube with 3 Swedish blades dedicated for wood,bone and metal. blade length is 12". You can see them @
www.montanajacks.com ( order the catalog). Unless you want to pack bowsaw blades ( 18-24") and fabricate a bow from greenwood this is the best option I know of.
www.crosscutsaw.com ( rough site navigation) sells traditional one and two man crosscut saws ( and other goodies). If you need a unit for a car this is a easily stored, human powered unit. The crosscut site explains the different tooth patterns as well. Your Missouri Hardwoods might require a dedicated hardwood pattern such as Champion or Tuttle.