That website is mostly geared to LIBERIA and to a lesser extent the Guanacaste beaches closest to Liberia (with a couple of hotels as far south as Samara). Montezuma is at the extreme southern tip of the Nicoya Peninsula, not easily accessible from the area covered by that website and not even actually part of the Guanacaste province. It may have a little information on transportation between SJ and the Montezuma area, but the website I've found with the best info on the southern Nicoya peninsula is
http://www.nicoyapeninsula.com/. It has a VERY complete section on Travel Information section including full ferry schedules, bus schedules, car driving info, flights and even info on how to drive directly between there and the Central Nicoya area.
The other website said it takes 5 hours to drive between SJ and Montezuma and that may not be a bad estimate for a private car. But it really all depends on weather, traffic AND your timing hitting Puntarenas and the ferry schedule.
Public buses can take 5.5 or 6.5 hours depending on when you leave SJ (7AM and noon departures take 6.5hrs and 10AM and 3PM departures take 5.5hrs). The one obvious advantage of them is that they only cost ~$10/pp each way.
The Interbus shuttle leaves at 9:15AM takes 6.25hrs and costs $39/pp. Their return shuttle costs the same and takes the same time but leaves a half hour earlier. The shuttle service booked through the website Cali gave leaves a little earlier then Interbus, is supposed to take a half hour less and has both a morning and an afternoon return departures but they don't list any prices, which I find kinda curious.
As for price for a private driver, your guess would be as good as mine, but IMHO picking a driver goes beyond purely a question of price and I'd imagine you might be better advised inquiring with one of the many drivers recommended on this board who are based in SJ for a ride between SJ and Montezuma rather than go through some outfit based in Liberia.
Personally, at $10 each way by bus for you and I assume your chica versus $40 each way by shuttle (and more choices of departure times), you'd stand to save $120 total and even more than that versus hiring a driver, so I'd go by bus. But I know you're a big fan of Interbus.
BTW, if you want to combine this trip with a visit to Jaco, you can take a water taxi from there for $35/pp (4pax min) in about an hour. I don't know if this interests you but it might interest some guys who are regular visitors to Jaco.
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As for hotels, a lot of that depends on what you're looking for. What are you looking to spend, luxury-level, budget or something in between? How long do you plan to stay? Some of the nicer places are also casita type places that rent by the week (I'll assume that's not what you're looking for). If you have a car or driver, you might prefer to be a little more outside of town and closer to "nature" and just drive into town when you want to go out to eat or party. Or you might prefer to be within easy walking distance of town or even in the thick of things, especially if you came in on the bus or a shuttle.
For higher end hotel accomodation,
Ylang Ylang Beach Resort is at the top of the heap. Whether it is worth the $250+ price is another question (They also have "cheaper" beachside rooms for as low as $190 green season). And it is about a 10 minute walk north from town and up a steep slope from the beach. You also didn't say when you're planning to go, but their website says they'll be closed for renovations for a couple of months starting in September.
At the budget end, you have
Hotel Luna Llena with single prices starting at $20/nt and dbls starting at $30/nt. They've been described as "rustic", but the pics look pretty decent to me and they get good reviews on TripAdvisor, plus they're located in town itself.
For a moderate priced place a little further outside of town that gets good reviews, you might want to check out the
Casa Colores (maybe 1/2 mile inland) or
Nature Lodge Finca los Caballos (maybe 1 mile inland). The drawback here is in addition to being further from town they're also a little further from the beach.
A nice place on the southern edge of town is
Amor de Mar. Or, if you can organize some other monger-chica couples to join you, they have some very nice looking houses with multiple bedrooms and nightly rates on the same property that you could split up or create your own group party (Casa Luna and Casa Sol). Unfortunately, the shore is rockier at this end of town (near the river mouth) but you get the ocean views and breezes and they're located just a short (<5 minute) walk from the center of things.
Finally, in town itself, you could try
El Jardin.