
The Hakone Free Pass is not a JR product, which is the first thing to understand about it. It is an Odakyu ticket, and it covers the loop of small railways, cable cars, ropeways and boats that make Hakone worth visiting in the first place.
Unlimited use of the Odakyu-affiliated transport network inside Hakone, plus a return trip from Shinjuku if you buy that version.
The Romancecar, Odakyu’s reserved limited express, needs a supplementary fare on top of the pass.
Hakone is designed to be travelled as a circuit rather than out and back, and the pass exists because the circuit crosses several operators. The usual direction is Odawara to Hakone-Yumoto, the Tozan railway up to Gora, the cable car to Sounzan, the ropeway over Owakudani, then the boat across Lake Ashi and a bus back down.
Buying each leg separately costs more than the pass in almost every case, which is why this is one of the few Japanese transport passes that is nearly always worth it if you complete the loop.

If you do the full loop, yes, comfortably. If you are going straight to one onsen and staying there, no. The Hakone area version at ¥6,000 makes sense if you are already staying locally or arriving by a route other than the Odakyu line.
The three day version costs only ¥400 more than the two day, so if there is any chance of a slower trip, take the longer one.
Owakudani is the volcanic valley the ropeway crosses, with steam vents and the black eggs boiled in the sulphur springs. Note that the ropeway occasionally closes at short notice on volcanic activity, and buses substitute.
Lake Ashi gives the classic view of Mount Fuji behind the red torii gate at Hakone Shrine, on the clear days you will need some luck to get. The Hakone Open-Air Museum near Gora is worth an hour, and the Okada Museum and Pola Museum are both strong.
Available as a digital pass through the Odakyu site or Klook, or as a paper ticket from ticket machines and offices at Odakyu stations including Shinjuku, and at points inside the Hakone area.
Unlike JR regional passes there is no Temporary Visitor restriction, so anyone can buy it.
No. It is an Odakyu product and entirely separate from JR. The two do not overlap, although a JR pass can get you as far as Odawara.
No. The Romancecar requires a supplementary limited express fare on top of the pass.
Three costs only ¥400 more. Unless your schedule is fixed and tight, take the three day version.
Yes. There is no visitor status restriction on this pass.