Just to give an idea of how big 300 rooms would be - you would have to combine*:
Journey's End Resort (70 rooms), Banana Beach Resort (66 rooms), Ramon's Village (61 rooms), Belizean Shores (48 rooms), Captain Morgan's Retreat (45 rooms), Lily's (10 rooms)
Well you can dream but it's unrealistic to think that you could build a 300-room resort with no infrastructure in place to support it. No roads, no water, no phones, no housing, no way of transporting large volumes of supplies and on and on.
You might get away with building it in the south end but the way things are even that would be a stretch. We don't even have enough water pressure to support Boca del Rio never mind a 300 room resort. Maybe in 10 or 15 years the infrastructure might be there but reality dictates otherwise at this time.
I'm assuming that the goal is to make money not to throw it away. Even with all the concessions that such a development would request (no taxes, no duties, no restrictions on labour pool, low interest or no interest loans from the government, immunity from loan defaults, immunity from EA's), you would still have a rough time pulling it off.
Let's face it, anyone who wanted to put together such a project would take one look at realities here and would walk away or build something more realistic. As far as benefits to the country or AC, the downsides would far outweigh the upsides.
One final thing on the road, it's taken years to get about a miles worth of paved road in the south end, where the majority of the population lives and where the greatest number of rooms exist (last count - 900 south, 350 north). What makes you think that there will be a road built for the north end anytime soon when most people are quite happy to have none?
I'm all for continuing development of the island but in a realistic way that benefits not strains the community.
*some numbers may be low due to ongoing construction.