As Tom mentioned, it's best to have your lisp routines in a "support path" and in a "trusted path", preferably outside your AutoCAD support files, like C:\MYLISPS
As well as an acaddoc.lsp (a file you create) which sets variables and loads routines, as well as ones loading when invoked by their commands.
Maybe you can add your jump drive\folders to those paths when you start working on each machine, not sure how it works when you unplug it though?
Sample of a basic "acaddoc.lsp"
Code:
(defun-q MYSTARTUP ()
(SETVAR "OSMODE" 703) ;;variables set when opening each drawing
(SETVAR "REGENMODE" 1)
(SETVAR "GRIDMODE" 0)
(SETVAR "SNAPMODE" 0)
(SETVAR "LIMCHECK" 0) ;; and so on
(PRINC)
(LOAD "FAVORITE LISP") ;; loads lisp routines every time (need to be in support and trusted paths)
(LOAD "ANOTHER FAVORITE LISP")
;;LISP ROUTINES INVOKED BY THIER COMMANDS
(AUTOLOAD "STL" '("STL")) ;;;STEEL SHAPES, COMMAND: STL
(AUTOLOAD "WELD" '("WLD")) ;;;WELD SYMBOLS, COMMAND WLD
(setq S::STARTUP (append S::STARTUP MYSTARTUP))