One of the greatest things that can be done is creating wealth for people, so as a hardcore utilitarian I would be an entrepreneur and create an extremely successful business. Once I learned how to do that well and make lots of money, I'd use that money to start and invest in new entrepreneurial ventures to create even more wealth. This would be extremely worthwhile to society as I'd be giving people what they wanted and for reasonable prices. After building up enough wealth I'd create firms for the sole purpose of investing in entrepreneurial ventures based on the knowledge I gained. Of course I'd automatically be giving money to an extremely inefficient form of charity (government), but if it ended up getting smarter and allowed me to spend money how I want instead of taking it from me and thinking it knows better what to do with it, then I'd donate to private charities for worthwhile causes.

This would all continue on long after my death. So yeah, that's the most I could do as a hardcore utilitarian (with any decent level of probability).