I can't recommend this country for a visit strongly enough. Plenty of historical interest and enough to keep the family happy with the weather, pool and beach. It is certainly cheaper than most European destinations when you get there, although flights, accommodation and care hire are similar.
The main military highlights included the Austrian forts built in the 19th Century to defend their main naval base at Cattaro (Kotor). The old fortified Venetian towns like Kotor, Perast and Budva. Plus, up into the mountains to the old royal capital Cetinje.
The museums are small but interesting. Here are a few of the exhibits at the excellent Kotor Maritime Museum.
and some more, this time from the National Historical Museum at Cetinje