Looking for a crater full of molten lava to throw an indestructible ring into? Look no further.
If you ever find yourself in a position where you need to destroy a ring of power, the closest place to find to a modern day Mordor is Hawaii Volcanoes National Park. Here, lava bursts from active volcanoes, flowing down the mountainside in molten rivers destroying (or rather, reshaping) the landscape in its path. You can even find a convenient crater of molten lava or two to toss an indestructible ring into if you so choose.
The best hike for halflings on a mission is likely the Halema'uma'u Trail. On this hike you'll discover a particularly active volcanic crater and a series of lava vents. If Halema'uma'u is quiet at the moment, head to Kilauea Iki Trail instead. Kilauea Iki is widely regarded as one of the best hikes in the national park. At times in the past, Napau Crater was a key hobbit destination, although it has quieted in recent years.
Once your ring-destroying mission has been accomplished, there's still plenty of sightseeing to be had on your journey back from Mordor. Consider stopping off at the Pu'u Loa Petroglyphs to view one of the largest petroglyph fields in Polynesia. Finally, for a longer hike with stunning ocean scenery, try out this loop from the Hilina Pali Overlook. Who said quests were all work and no play?!
DISCLAIMER: Please don't actually throw anything in the volcanic craters.