I see, just realized what you used [swimming] for, whether you're [indoors] or [outdoors] you'll use Travel Form so long as you're swimming.
And doofus(the OP), if you're not adverse to using modifiers you can always use Alt, Shift, and/or Ctrl.
Code:
#showtooltip
/cast [mod];[nocombat,form:0/2,indoors]Prowl;[outdoors][swimming] Travel Form;Cat Form
/cancelform [mod,form]