Just to clarify... Salute tickets are not MYW. They are their own type of ticket. Shades of Green also sells discounted Magic Your Way tickets; these are not as highly discounted as the Salute tickets but are not as restricted -- more than 6 per year, more variability in length of ticket, etc.
What kind of military ticket do you have? Salute tickets include hopping. MYW tickets are available as either "base" tickets which are 1-park per day (no hopping) or "park hoppers" which allow you to visit 1 or more parks in the same day.
Both types require a theme park reservation. It's usually very easy to change, but it is subject to availability of reservations.
All tickets allow a guest to leave and return to the same park in the same day.
Park-hopping is no longer restricted to after 2pm.