Hello I am playing Devil's advocate here -
First, drainage problems in a neighborhood across the highway are due to the fact that the subdivision was built in a flood zone / wetlands overflow of a huge coastal lagoon. I don't know if it is actually on the flood zone map, but nevertheless people built too close to the lake with no planning. The neighborhood has no drainage plan, mostly unpaved streets that drain right in to the lake. Not good for the lake. Although any hotel needs to have an adequate drainage / stormwater retention plan of its own.
Second, although the accesses nearby you mention are really only useable by nearby houses due to no parking, why should that preclude any development? Where is it written that a hotel needs to have nearby plentiful access? Ideally yes, but not necessary to get a major development order approval. Arguing that the accesses will not handle additional people is like trying to tell people not to visit the beach.
I suggest you get a good attorney to argue compatibility issues as mentioned in major development order process. Also a detailed traffic analysis may be required.
The politicians may want to side with the voters if there is enough noise but they have to be given legal reasons to vote against it.
If runoff is coming from the north side of 30A, then it is related. Brown St. is 5 blocks away from Eastern Lake so it's proximity to the lake is not the only issue.
If sufficiency of nearby accesses isn't a consideration for the bureaucracy and politicians, it should be. They're not proposing that specific location so people can get to the outlet malls or Pier Park. They're there to go to the beach. Overloading the nearest neighborhood accesses with that size of a development, especially when one of those accesses is already out of commission due to the outfall, is irresponsible.