The worst project you can be on is one:
1. With no clear goals, he has no idea what he wants.
2. No support team; basically, like you said, you're the team, and even worse, you're "green".
It sounds like you got one of those "pie in the sky" projects; there's no clear benefit that the CIO can get from this, and if you succeed, he looks awesome; if you fail, he doesn't care, it's one of those "throwaway" projects.
In a megacorp, you have to get into a project which is directly involved in their day to day business, directly contributing to revenue, to get more recognition, resources, and $$$. Get into such a project, or make yours give some visible benefit to the company.
In your example, I'd have tried to pivot it to be a reporting tool; I find that senior management in banking generally have a poor visibility in their business monitoring, current transaction levels etc; this can give clear and visible benefit to the company.
Once you can show the benefits to your Boss and the CEO, the extra help and resources will follow.
They needed someone to rewrite a stagnant product they offered their clients. Essentially it was a white-label online wizard for selling accessory products to auto loans. All the sales logic itself was handled by a backend elsewhere, I just wrote a front end for it and tool for quickly creating a custom version with a client's logo and color scheme.
In the end I learned some .Net, some Javascript and even more about working within a large organization. I don't regret that summer at all.
It was the first time I was expected to write code that actually did something besides get me a grade on a homework assignment.
I was an intern in college getting a CS degree, just finished my senior year. I had an summer internship lined up with a small company but they folded at the last minute so I had to scramble for something to fill my summer. I wound up as an intern at a financial firm. Fairly large but not one you've probably heard of.
I was told that I'd be on the mobile development team. They knew I didn't have experience but I said I was eager to learn.
Turns out, there was no team. I was the team. The CIO had decided that they needed an iPhone app, despite being an entirely B2B company with virtually no consumer brand awareness, and he'd already sold the corner office crowd on the idea.
Problem is, no one in IT wanted to build it. The CIO had no clue what he actually wanted, they were understaffed as it was and no one had the time.
Enter me.
In my first meeting with the CIO, he pulled out his iPhone, went to m.msn.com and said "I want this but for $COMPANY." I went back and laughed in my cube for a while. I think he just liked the news article carousel MSN had.
My boss had talked him down to a mobile website which I began throwing together in jQuery Mobile. A few loan calculators and some contact info. I had a few ideas for something more aggressive but I got shot down as they needed me on other projects anyways. They had me spending a few hours a week on mobile dev just to keep the CIO happy.
My internship ended right as the CIO was bringing in a big consulting firm to replace everyone. And that's the story of how I decided not to work at a megacorp.